The influence of the I-Ching and the five elements on Taoism is enormous.

    First, The Theory of Yin And Yang And the Five Elements And The Teachings of Taoism

    At the end of the Warring States period, the alchemist Zou Yan combined the theory of yin and yang with the theory of the five elements to form the theory of the “five virtues of the beginning and end,” and used this theory to construct the cosmology, historical view, and theory of the dissolution of the physical world of the Fangxian Tao, as well as the theory of things that are attached to ghosts and gods. The Fangxian Tao of the pre-Qin period was the predecessor of Taoism, so Taoism has long been closely related to the theory of yin and yang and the five elements in terms of its ideological roots. The Taoist priests of the Han Dynasty continued to incorporate the theory of the five elements into Taoism, and the most obvious manifestation of this was the emergence of the Taiping Jing. The Taiping Jing is a Taoist classic that “uses the five elements as its foundation,” and the theory of the five elements is the main theoretical basis of the Taiping Jing. It is believed that the five elements embody the principles of the Tao, which are constant and unchanging, and that people must absolutely obey them and not lose their way. “The Tao has no strange words, and one yin and one yang are its use. Those who understand it will prosper, those who do not will fall into chaos; those who understand it will be wise and clear, those who do not will not be able to follow the Dao. The principle of yin and yang is found in all things in the world, and it is the Dao. No matter how big or small the matter is, if it follows the Dao, it will be safe. If the Dao is lost today, it will lead to chaos. Therefore, if the yang is safe, all things will be self-generating, and if the yin is safe, all things will be self-forming. The relationship between yin and yang can be mutually generated and transformed. The extreme of yin gives rise to yang, and the extreme of yang gives rise to yin. When yin and yang complement each other, the way is then possible. Other works such as “Laozi's Commentaries” and “Zhouyi's San Tong Qi” are closely related to the theory of yin and yang and the five elements.

    Second, the theory of the five elements and the Taoist pantheon

    The idea of yin and yang and the five elements influenced the ancient religions that were the predecessors of Taoism. The ancients attributed the attributes of “yin and yang” and “the five elements” to the gods they worshipped, creating a network of gods and spirits. This idea was completely preserved by Taoism. For example, the Eastern Emperor and the Queen Mother of the West, also known as the Wood God and the Golden Mother, are worshipped by Taoism. The Taiping Yulan (Taiping Encyclopedia) volume 668 quotes the Jixian Luo (Book of Immortals) as saying: “Mu Gong and Jin Mu are the ancestors of the two energies, the original source of yin and yang, the masters of the immortals, the first of creation, the condensation of energy into reality, and the union with the Dao. Another example is the Zhenwu Dadi (or Xuanwu Dadi), who is the god of the north in the Daoist system of immortals (the north is water in the five elements). This kind of Daoist god with invisible attributes of yin and yang is also reflected in the inner gods. According to the theological ideas of “unity of heaven and man” and “heaven and man are in harmony,” Taoism believes that the human body is also a small world, and that the gods in the world have corresponding existences in the human body. There are gods of heaven and earth, yin and yang, and the five elements, and there are gods of the heart, the left yin and right yang, and the five zang organs and the five elements. The yin and yang attributes of the gods in heaven and the gods in the human body are similar and connected.

    Third, the relationship between the philosophy of the I Ching and Taoism

    Taoism uses the ideas and symbolic system of the I Ching to explain the movement and changes of all things in the universe, and uses these changes to guide the cultivation of the human body in order to achieve harmony with nature. At the same time, it proposes corresponding ways of change for the governance of society. The cultivation of the human body is most closely combined with the ideas of the I Ching (mainly the I Ching of the Han Dynasty), and the most prominent manifestation of this is in the “Zhouyi San Tong Qi”. “Zhouyi San Tong Qi” is the earliest work of Taoism that combines theory and practice in the cultivation of the alchemy of the Dao. Its central idea is to use the Yin-Yang theory revealed in the Zhouyi to explain the alchemy of the furnace, and the natural principles of Huang Lao, and it is the fundamental text for the later internal and external alchemy.

    From the perspective of Taoist rituals, Taoist talismans and internal and external alchemy are closely related to the study of the I Ching. A talisman is a kind of graphic symbol that resembles a character but is not a character. Taoism believes that it can “exorcise ghosts and command spirits” and “subdue demons and suppress evil spirits.” Taoism uses the I Ching to create talismans, and the Daozang contains many talismans named after hexagrams.

 《易》学和阴阳五行思想对道教的影响巨大。

  第一，阴阳五行理论与道教教义

  战国末期的方士邹衍将阴阳学说合五行学说结合起来，形成了“五德终始”理论，并运用这种理论构造了方仙道的宇宙构成论、历史观、形解销化之术及依附于鬼神之事的理论。先秦的方仙道乃是道教的前身，故而道教从其思想根源上讲，早已与阴阳五行说有密切关联。汉代的方仙道家们更是不断的将阴阳五行学说运用到道教的教义之中，最明显的体现是《太平经》的出现。《太平经》就是“以阴阳五行为家”的道教经典，阴阳五行说是《太平经》的主要理论基础。认为：阴阳五行体现天道之理则，恒常 不变，人须绝对顺从，不可失其道。“道无奇辞，一阴一阳，为其用也。得其治者昌， 失其治者乱；得其治者神且明，失其治者道不可行”。一阴一阳之理，遍于天地，为道 之用。事无大小，皆守道而行，故无凶。今日失道，即致大乱。故阳安即万物自生，阴 安即万物自成。阴阳之关系可互生互变，阴极生阳，阳极生阴，阴阳相得，道乃可行。其他如《老子想尔注》、《周易参同契》等，莫不与阴阳五行学说密切相关。

  第二，阴阳五行说与道教神仙谱系

  阴阳五行的思想影响到道教的前身之——古代宗教，古人对崇祀之神赋予“阴阳”、“五行”的属性，网络了神灵世界。这种思想被道教完全的保留了下来。如道教崇奉的东华帝君与西王母，亦称木公、金母。《太平御览》卷六六八引《集仙箓》曰：“木公、金母者，二气之祖宗，阴阳之原本，仙真之主宰，造化之元先，凝气成真，与道合体”。又如真武大帝（或称玄武大帝），在道教神仙体系中是职司北方的神（北方在五行中属水）。道教的这种具有阴阳无形属性的神还体现在身内神上。道教据“天人合一”、“天人感应”的神学思想，认为人体也是个小天地，天地间有的神灵在人体内都有对应的存在。天上有上帝及阴阳、五行之神，人体有“心君”及左阴右阳、五脏五行诸神，天神与人体内诸神的阴阳属性相类相通。

  第三，易学思想与道教的关系

  道教运用易学的思想和符号系统来说明宇宙万物的运动变化，并通过这种变化来指导人体的修炼，以达到与自然的和谐同一；同时针对社会的治乱提出相应的变通之道。其中人体的修炼与易学思想（主要是汉代易学）结合的最为紧密，突出的表现体现在《周易参同契》中。《周易参同契》是流传至今的道教丹鼎修炼最早的理论和实践相结合的著作。其中心思想是运用《周易》揭示的阴阳之道，参合黄老自然之理，讲述炉火炼丹之事，后世的内外丹经莫不以此经为认证的根本。

  从方术仪式来看，道教的符箓和内外丹术皆和《易》学密切相关。符箓是一种似字非字的图形，道教认为它“可谴鬼役神”，“镇魔压邪”。道教依《易》造符箓，《道藏》中保存不少以卦命名的符箓。