Abstract: The hereditary characteristics of 8 T1 lines harboring two insecticidal genes were studied via PCR analysis and cross test, the results showed that the insecticidal genes transmitted as Mendel rule of 3:1 in 6 lines. In one line, the ratio of positive plants for insecticidal gene to negative ones was approximately 15:1, indicating that the insecticidal genes might be incorporated in the two unlinked loci in the genome. In another line, the ratio was significantly deviated from the ratio 3:1 (approximately 1:1) and the further study showed that the phenomena might be related to decreased competing ability of transgenic pollens.