Abstract: look into the new method of applying HG-AFS on disposable digestion sample to measure how much Arsenic, Selenium and Mercury in it. Under selected laboratory enviroment, got the RSD of Se, As, Hg are respectively 3.7%, 2.8% and 4.7%; recovery rates are 95.0%, 102.0% and 91.9%; indicating that this method is fast, simple and accurate. Compared to National Standard Method, can be disposable digestion sample to measure the weight of three elements continuously, not only simplifies the operation, quickens the measure speed, but also reduces reagent consumption and improves the efficiency. It is worthy of popularization and application .