Abstract: The strongest electroantennogram (EAG) response was evoked by Z-9-tetradecenyl acetate (A), Z-11-hexadecenyl acetate (B), Z-11-hexadecenal (C) and Z, E-g, 11-tetradecenyl acetate (D) to the antenna of the male moth of the pine tip moth Dioryctria rubella Hampson (Lepidoptera: Pyralidae). The biol ogical activities of the four compounds in different proportion were confirmed in field tests. The tests showed that the combination of three compounds(B,C and D) is a sex attractant for the male and optimum ratio is 1:7:2 in naturaal rubber septa. The other EAG active compounds A inhibit the effect of trap catch of the B, C and D compounds. Traps baited with the three compounds caught more males than those baited with females did.Male moths were collected in the field with the sex atfractant trap that can monitor populations of the pine tip moth.