Abstract: A turbidimetry for the determination of chlorine in antimony pentoxide powder was established. The experimental conditions of dissolution method, concentration of nitric acid, sample mass, and dissolution time were studied. The results showed that the sample mass of antimony pentoxide powder was 0.5000 ~ 1.000 0 g and the solution was dissolved in 10% nitric acid solution for 2 h. The spiked recoveries of chlorine in the sample were 96.20% ~ 99.13%, indicating the high accuracy of the method. At the same time, 11 parallel experiments were carried out, and the relative standard deviations were all less than 5%, which showed that the method has a good accuracy and repeatability.