Fifty-two Bt/CpTI transgenic cottons from home and abroad have been used to study insect resistance to Helicoverpa armigera and Laphygma exigua. The tested varieties were planted in the diseases-free experimental field and insect-resistance was determined in the laboratory, It was showed that the resistance of China-bred varieties to the second-generation H, armigera was lower than that of the varieties introduced from abroad, As to the third-generation H, armigera, China-bred varieties were somewhat higher than the overseas varieties. Xinmian 33B had higher resistance to L. exigua, The Bt and CpTI transgenic varieties showed low resistance to L. exigua. According to identification of insect-resistance, 15 varieties were screened out with higher resistance to the second and third-generation H. armigera and Xinmian33B with higher resistance to both H, armigera and L. exigua.