Abstract: To determine the influence of second-generation Asian corn borer (Ostrinia furnacalis) (Guenée) on corn yield, we simulated the damage caused by Asian corn borer under natural conditions, to study the economic threshold of the secondgeneration Asian corn borer in Liao-ning. Field tests were conducted to infest the spring corn LD565 with a series of egg mass numbers (0, 20, 50, 100 and 200 eggmasses per 100 plants). Correlation analysis revealed that egg mass number per 100 plants showed a significant positive correlation with stalk hole number per 100 plants (P<0.01), with a regression equation y=3.1999x+24.8416 (R²=0.953, P<0.01); stalk hole numbers per 100 plants showed a significant positive correlation with yield loss rate (P<0.01), with a regression equation y=0.0234x-1.6167 (R²=0.988, P<0.01). The correlation between the number of eggmasses per 100 plants and corn yield loss rate met the equation z=0.0749x-1.0354, meaning that stalk holes would increase by 3.2 and maize yield loss would increase by 7.49% with per one increase in egg mass number. Tunnel length showed a negative correlation with ear length, ear diameter and yield weight per plant (P<0.01), while a positive correlation with yield loss rate (P<0.01). Maize yield loss would increase by 4.38% with per 10 cm increase in tunnel length. In conclusion, the economic threshold of applying richogramma dendrolimi Matsumura to control Asian corn borer would be 17.39 eggmasses per 100 plants in the field with a grain yield of 8411 kg·hm^-2.