Abstract: Sterile effects of hexamethyl phosphoryl triamide (i.e. HMPA) on Bactrocera dorsalis (Hendel) adults were studied in laboratory. The results revealed that number of eggs produced by females did not decrease in the treatment of 0.01% concentration, while the hatching ratio of eggs did obviously. Treatments in concentration of 0.10% and 0.20% could cause the females completely sterile.When only males were treated by 0.2% concentration, the number of eggs produced by the females which mated with treated males decreased obviously, and the hatching rate was entirly surpressed. 0.20% concentration of HMPA was most suitable in steriling Bactrocera dorsalis adults.