In greenhouse, the F1 and F2 hybrids derived from glufosinate resistant transgenic rice (Y0003 and 99 1) and Malaysian weedy rice or Anhui weedy rice were backcrossed with corresponding weedy rice to obtain backcross generations. And the seed setting rates of the backcross were counted. The proportions of plants carrying the glufosinate resistance gene in F1 or F2 hybrids and the backcross generation were calculated. In order to comprehensively assess the risk of gene flow from glufosinate resistant rice to weedy rice, the fitness of hybrid and backcross generations were observed. The results showed that the hybrid generations were able to backcross with corresponding weedy rice with seed setting rates from 15% to 60%. The seeds from reciprocal hybrid F1 generation showed favorable glufosinate resistance, but F2 and backcross generations showed a normal 3&amp;#8758;1 and 1&amp;#8758;1 Mendelian segregation with glufosinate selection. The fitness of hybrid and backcross generations didn&amp;#8242;t differ obviously from that of their corresponding weedy rice. Most hybrid generations displayed similar fitness with backcross generations, but some hybrid generations were lower than backcross generations in fitness. All above results indicate that hybrids and backcross generations of two weedy rice carrying glufosinate resistance genes of Y0003 and 99 1 could survive under benign conditions without herbicide selection.