As while as the development of transgenic technology creates enormous economic and social values, more attention has been paid to its safety. At present, the planting area of herbicide-resistant crops is the largest in transgenic crops. In this paper, the characteristics and safety of bar gene, PAT proteins and glufosinate were expatiated. The bar gene and glufosinate play important roles in plant engineering, and bar sequences are considered to be as safe as any other DNA in food and have no pleiotropism. ...