Objective To explore effects of microwave digestion and wet digestion method in the pretreatment of food (rice noodles and flour) on determination of total arsenic in food. Methods According to the national standard second GB 5009.11-2014 method (hg-afs), microwave digestion and wet digestion method for the determination of total arsenic in quality control samples and sample digestion was used. Results Determination of total arsenic was tested in food by two methods. When its content was 0.726mg/kg, the precision and accuracy (recovery rate was 112~115%, RSD<2%) was both higher. There was no significant difference in the test results of the samples (t=0.723,P>0.05). When its content was 0.317mg/kg, the accuracy of wet digestion test was very high (RSD<2%, z≤2). The total arsenic content was 0.222mg/kg detected by microwave digestion method, which was 70% of the quality control sample(RSD=2.8%).The difference between the two methods was statistically significant (t=7.491, P<0.05). According to the national standard, the total arsenic content in cereal limit was 0.5 mg/kg. This experiment with this value was as a boundary value. The sample with value less than 0.5 mg/kg was called sample with low total arsenic content, and sample with value higher than 0.5 mg/kg was called sample with high total arsenic content. Conclusion When the total arsenic content was high, the methods of microwave digestion and wet one in the pretreatment of food (rice noodles and flour) were in good agreement. When the total arsenic content was low, the wet digestion method was reliable.