Abstract:Risk assessment is paid increasing attention along with the more and more releases of transgenic crops. Gene flow between transgenie crops and their wild related species is the main issue in the risk assessment. Transgene may escape spatially by pollination and escape temporally via seed bank as well. The formation of hybrids between transgenic crops and their wild related species is the evidence of spatial escape of transgene, that is the beginning of temporal escape of tmnsgene. Many factors may influence the formation of hybrids between transgenie crops and their wild related species, and the fate of hybrids as well. The dispersion of crop pollens was studied with statistical models 50 years ago, and current mathematical models for describing the transgene escape are greatly improved. Physical isolation and the application of male sterile euhivars may prevent the dispersion of transgenic pollens, but it may not thoroughly cut off the gene flow between transgenie crops and their wild related species. The experience and knowledge obtained from small scale release have to be further deliberated as these will be used for risk assessment on commercialized release.