RÉSUMÉ
Objective]To summarize and clarify the view on Yin and Yang of Zheng Qin-An ,in order to deepen the study on fire-spirit school. [Method]Read the related works of Chen Xiu-Yuan, Liu Yuan, Zheng Qin ’An, Lu ZhuZhi, etc, as wel as related research papers of modern researchers. Then we summarize the view on Yin and Yang of Zheng Qin-An, as wel as it ’s resources and evolution. [Result] Zheng Qin-An advocated the balance of Yin and Yang, didn’t admire Yang and despise Yin. He also had no preference on Yang aided medicine. Zheng Qin-An ’s view on Yin and Yang mainly was affected by Liu Yuan, and significantly different from Chen Xiu-Yuan. Lu Zhu-Zhi inherited the academic point of view of Zheng Qin-An and made some significant changes. After that, fire-spirit school only emphasized the importance of Yang Qi. Developed to the extreme, some fire-spirit school scholars held that al patients were Yang deficiency and al prescriptions should aid Yang Qi. These views had deviated significantly from its founding fathers. [Conclusion]Zheng Qin-An advocated the balance of Yin and Yang, but his successor ’s only emphasis on the importance of Yang Qi, was contrary to the original intention of Zheng Qin-An.