Abstract: A method to determine As in soil sample that digested with aqua regia in microwave oven without dispelling acid and determined by HG-AFS is to develop. The results showed that the tested value of arsenic in microwave digestion with aqua regia without dispelling acid was within the recommended value of ESS-1. Under optimal conditions,the linear range of arsenic was at 0.0~50.0 μg/L, the correlation coefficient was 0.9995; The parallel determination was done 4 times by ESS-1 and GSS-2; the relative standard deviation was 0.39%~4.56% respectively; The recovery of arsenic was 93.4%~100.9%;The detection limits of arsenic was 0.5 mg/kg. The results suggested that the method is simple to operate with high accuracy for the determination of the content of arsenic in soil sample by atomic fluorescence spectrometry with microwave digestion.