Abstract: The biological activity of fenoxicarb on tobacco beetle (Lasioderma serricorne) larvae was determined with dropping method, and the control effect was experimented in laboratory and store house. The results showed that fenoxicarb had no evident acute contact lethal activity against the larvae, however, there existed significant juvenile hormone-like after effect.The control effect of Fenoxicarb on tobacco beetle and tobacco moth was 100%300 days after treating tobacco leaves at a concentration of 10-20mg/kg.