Abstract: The toxicity of three insecticides,imidacloprid,acetamiprid and buprofezin to Trialeurodes vaporariorum,Chrysoperla sinica and Orius minutus was studied in laboratory and the selective toxicity between T.vaporariorum and two natural enemies was compared.The results showed that these three pesticides showed high toxicity to all stages of T.vaporariorum and the LD50 values ranged from 0.28 to 4.17 mg/L.For C.sinica,the LD50 values of imidacloprid,acetamiprid and buprofezin were 16.59,178.2 and 10 286 mg/L to eggs respectively,were 54.08,22.79 and 215.5 mg/L to the 2nd instar larvae respeitively,and were 20.06,26.05 and 1 836 mg/L to adults respectively.The LD50 values of the three pesticides to adults of O.minutus were 62.14,8.92 and 170.9 mg/L,respectively.Imidacloprid,acetamiprid and buprofezin showed good selective toxicity between T.vaporariorum, C.sinica and O.minutus,and buprofezin had the highest selective toxicity among these three pesticides,which was important to the integrated control of T.vaporariorum.