Eleven transgenic Cry1Ac+API-B cotton lines were evaluated on the agronomic traits, like resistance to cotton Bollworm, yield and fiber quality traits. Compared with their receptor ‘Ekang 9’, distinguished resistance to cotton bollworm was found among these transgenic lines, and most of them presented moderate resistance or high resistance to bollworm. Moreover, significant differences were also found in yield and yield related components between transgenic lines and ‘Ekang 9’. All transgenic lines decreased in lint percentage and lint index. But other agronomic traits like plant height, number of fruit branch, bolls per plant and fiber quality traits like length, micronaire and strength varied in different directions compared these transgenic lines with‘Ekang 9’.