The larvae of the Asian corn borer, Ostrinia furnacalis (Guenée), were treated for 2 h in the laboratory under the temperature 5℃ (LT1) and 0℃ (LT2), respectively. The discriminating temperature, survival rate, cold tolerance, super-cooling point, and the rates of water and lipid in the Asian corn borer larvae after low temperature treatment were determined, respectively. The special antifreeze protein in the serum of the 5th instar larvae of O. furnacalis after low temperature treatment was analyzed with SDS-PAGE. The results showed that the discriminating temperatures for the 3rd, 4th and 5th instar larvae were -13.5℃, -16.5℃ and -18.5℃, respectively. The survival rates of 3rd, 4th and 5th instar larvae all showed the tendency of LT2>LT1> the control group after low temperature treatment (P<0.05). With the increase of instar, the cold tolerance of the larvae increased gradually, and the rates of water and lipid in the larvae also increased significantly (P<0.05). The super-cooling point of the larvae was not effected significantly by low temperature (P>0.05). The rates of water and lipid in larval body showed the tendency of LT2>LT1>the control group after low temperature treatment. A special antifreeze protein with the molecular weight about 29.0 kD was detected in the 5th instar larvae. It was so concluded that low temperature treatment could increase the cold tolerance in the Asian corn borer larvae. 19 Refs. In Chinese.