Abstract:Effects of CpTI+Bt transgenic cotton (SGK321) and Bt transgenic cotton (Kemian3) on the survival, growth, reproduction and preference of Spodoptera exigua (Hübner) were tested in laboratory with Simian3 as the control. The results indicated that mortality of larvae, decrease rates of pupate and adult moths developed from larvae fed on SGK321 and Kemian3 were significantly higher than those on CK, and the decrease rate of pupate developed from fed on SGK321 was significantly higher than that on Kemian3. Duration of larvae fed on SGK321 and Kemian3 were significantly longer than CK, in contrast, pupa weight which developed from larvae fed on SGK321 and Kemian3 was significantly lower than CK. Duration of larval fed on SGK321 was longer than that on Kemian3, and pupae duration and weight on SGK321 were similar to that on Kemian3. Preoviposition period, oviposition duration and mean fecundity of adult females developed from larvae fed on three kinds of cottons were SGK321＜Kemian3＜Simian3, and oviposition duration of adult female on SGK321 was significantly shorter than CK. The life-span of adult female on SGK321 was similar to that on Kemian3, but significantly shorter than CK. The net re- productive rates(R0), intrinsic increase rates(rm), finite increase rates(λ)and index of population trend (I)on three cottons were SGK321T)and doubling times of population(DT)were SGK321>Kemian3>Simian3. Preference of 2nd to 5th instar larvae was Simian3>Kemian3>SGK321.