The Green Dragon was originally the god of the East in ancient mythology and one of the four symbols of the Seven Stars of the East in Taoism. It is one of the 28 constellations of the East (Jiao, Kang, Di, Fang, Xin, Wei, Ji), which is a dragon in shape, located in the East, belonging to wood, colored green, and collectively known as the Green Dragon, also known as the Canglong. The “Taishang Huangluo Zhaiyi” volume 44 calls the “Eastern Dipper Star Lord” the “Dragon Lord of the East”: “Jiao Su Tianmen Star Lord, Kang Su Tingting Star Lord, Di Su Tianfu Star Lord, Fang Su Tiansi Star Lord, Xin Su Tianwang Star Lord, Wei Su Tianji Star Lord, Ji Su Tianlv Star Lord.” As for its image, the seventh volume of the “Taoist Collection of Essential Teachings” says: “The essence of the dragon's horn in the east, spitting out clouds and mists, shouting thunder and making sounds, flying eight poles, traveling the four realms, and standing on my left. In addition, Taoism also uses it in alchemy terminology, such as the “Yun Ji Qi Lian” volume 72, which quotes the “ancient scriptures” as saying that the Dan of the four gods is: the blue dragon, the eastern wood, mercury, is not emotional when it is clear, not turbid when it is stirred, not close to take, not far to leave, hidden changes endless, so the dragon is also said.

　　青龙原为古老神话中的东方之神，道教东方七宿星君四象之一。为二十八宿的东方七宿(角、亢、氐、房、心、尾、箕)，其形象龙，位于东方，属木，色青，总称青龙，又名苍龙。《太上黄箓斋仪》卷四十四称青龙东斗星君”为：“角宿天门星君，亢宿庭庭星君，氐宿天府星君，房宿天驷星君，心宿天王星君，尾宿天鸡星君，箕宿天律星君。”至于其形象，《道门通教必用集》卷七云：“东方龙角亢之精，吐云郁气，喊雷发声，飞翔八极，周游四冥，来立吾左。此外，道教还将其用于炼丹术语，如《云笈七籖》卷七十二引《古经》四神之丹称：青龙者，东方甲乙木水银也，澄之不情，搅之不浊，近不可取，远不可舍，潜藏变化无尽，故言龙也。