Abstract: Based on the identification and selection of the piping in the continuous flowing analyzer and the sample purification using graphitized carbon black solid phase extraction column, ammonia in cigarette mainstream smoke was determined by the method of continuous flowing analysis. Results showed that the content of ammonia was 2.46¹0.40μg/cig, which was in good agreement with that of the ion chromatography. Recovery rate of the method was 91 . 3 % ~ 97 . 9 % , and the repeatability was performed at one day and different days of RSD <3.5% and RSD <2.0% . Results indicated that the method was suitable for rapid and accurate determination of ammonia in mainstream cigarette smoke.