Objective To explore the curative effects of Yuyin Qianyang Decoction on Parkinson syndrome caused by antipsychotics and its influence on the quality of life. Methods A randomized double blind case control study was designed. A total of 120 antipsychotic induced Parkinson syndrome patients were randomly divided into study group（ n=60） and control group（ n=60）. Patients of the two groups were given Yuyin Qianyang Decoction combine with trihexyphenidyl placebo and trihexyphenidyl combined with Yuyin Qianyang Decoction placebo respectively. All the patients were treated for 12 weeks. Abnormal Involuntary Movement Scale（ AIMS） and Mos 36-item Short Form Health Survey（ SF-36） were applied to evaluate patients' curative effects and quality of life before treatment and 4， 8 and 12 weeks after treatment. Results There was no statistical difference in curative effects of antipsychotic induced Parkinson syndrome between the study group and control group（ F=0.186，P＞ 0.05）. However， there were significant differences among different time points （F=70.180， P＜0.05）， and the interaction among different time points and groups was not significant（ F=0.939， P＞ 0.05）. After treatment， the SF-36 score of the study group increased significantly in physical function， role of physical， bodily pain， vitality， social function， role of emotion， mental health， physical component summary and mental component summary（ P ＜ 0.05）. Before treatment， there was no statistical difference in SF-36 between the two groups. After treatment， the scores of study group were significantly higher than those of the control group in role physical， role emotional， mental health， reported health transition， physical component summary and mental component summary（ P＜ 0.05）. Conclusions The Qianyang Decoction showed almost the same effect as trihexyphenidyl in treating antipsychotic induced Parkinson syndrome， but it can improve the quality of life of the patients.