Abstract: This paper reviewed geographical distribution, flowering habits, hybridization compatibility, viability and fertility of hybrids, progeny and their backcross generations in China based on the life cycle of B.napus and its relative species. In view of the current research and environmental release of worldwide, the risk of gene flow between transgenic rapeseed and its relative species was generally assessed. We concluded that the possibility of gene flow from transgenic rapeseed to its wild weedy relatives was relatively low, and key to control gene flow from transgenic B.napus may be reducing the transmission probability of transgene to B.rapa and B.juncea under China environment.