The optimal sterile concentration range of HMPA (hexamethyl phosphoryl triamide) against Bactrocera dorsalis was tested by feeding B. dorsalis adult with different concentration of HMPA dissolved in honey water. When normal female mates with the male treated with 0.05%HMPA, the hatching rate of their laying eggs was about 6%. The eggs don’t hatch when males were treated with the concentration of 0.09%. However, treatment of female adults with 0.07% HMPA resulted in a complete sterility. Based on the above results, the sterile effect of HMPA dissolved with 5% protein hydrolysate against B. dorsalis was studied by feeding B. dorsalis adult with concentration 0.02%, 0.04%,0.06%,0.08% and 0.10%. The results indicated that fecundity decreased with the concentration. The egg hatching rate was only 14% after feeding the males with 0.08% HMPA. But the egg hatching rate in the control group was up to 76%. The female adults were sterilized completely when the concentration was 0.08%.