Objective To explore the influence of pretreatment on the result of determination of total As in foods. Methods By means of wet digestion and microwave digestion, under different acid-driving conditions, the total As content in standard material, wheat flour, was detected by HG-AFS, and the result was compared with the standard value. Results Accuracy of the detection results was influenced by the procedure of the acid-driving pretreatment, and the amplification of the pollution weight of the detected element made the results higher than the credible range of the standard value.Conclusion The result of detection value of the standard material can be made within the credible range of the standard value, if the temperature during acid-driving is strictly controlled according to the boiling point of the acid used for digestion.