Objective To investigate the effect of adding hydrogen peroxide during microwave digestion on the determination of total arsenic content in rice flour. Methods According to the national standard GB 5009.11-2014 for the determination of total arsenic,hydrogen peroxide was added for microwave digestion of pre-treated samples,and the internal quality control samples from rice flour with total arsenic content were detected.The total arsenic content in the samples was determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS),respectively. Results The samples were digested by microwave digestion method,and the total arsenic content in the samples was determined by ICP-MS method.The results of the non-hydrogen peroxide group and the hydrogen peroxide group were 0.386±0.030 mg/kg and 0.355±0.022 mg/kg respectively.The difference between the two groups was statistically significant (t＝6.293,P＜0.05).The results of AFS method were 0.284±0.002 mg/kg in the non-hydrogen peroxide group and 0.307±0.014 mg/kg in the hydrogen peroxide group,and the difference between the two groups was statistically significant (t=8.979,P＜0.05). Conclusion The results of microwave digestion with hydrogen peroxide in pre-treating the rice flour sample were more accurate and reliable.