A new chemiluminesence method for the determination of promethazine hydrochloride with flow injection technique was-developed. The method is based on the chemiluminescence reaction between KMnO4 and promethazine hydrochloride, C2H2O2 can increase the chemiluminescent intensity. The detection limit is 3.5 x 10(-8) g/mL, the relative standard deviation is 2.8% (1.0 x 10(-6) g/mLpromethazine hydrochloride, n = 11). The linear range is 1.0 x 10(-7) similar to 6.0 x 10(-5) g/mL. The method has been applied to the determination of prometnazine hydrochloride in tablets and injections.