Rice is one of the most important food crops in China, a staple food for over 800 million people. Diseases, pests, weeds, harsh climate as well as other stress conditions severely retard high and stable rice yields. Transgenic technology has offered a novel means to breed rice varieties and cultivars against these stresses. In China, many GM (genetically modified) varieties and cultivars of rice resistant to some diseases, pests, weeds, and abiotic stresses have been generated since the 1980s, which have the potential to improve rice productivity and food security of China. On the other hand, the potential gene horizontal transfer and release into environment of GM rice might cause a serious issue of biological and environmental safety. Former papers have demonstrated that foreign genes would flow to nontransgenic cultivars and wild relative species by outcrossing. For example, under different experimental conditions, transferred herbicide resistance genes showed a frequency from 0.05% to 0.53% to escape, while the most probability drifting to male sterile lines was up to 4.518%. At the same time, the highest average drifting frequency from insectresistance transgenic rice to neibouring nontransgenic rice was 0.875%. In this article, several key aspects of the GM rice were addressed, including the hybridization of rice cultivars with their wild relatives, the transgene flow from GM rice to nonGM rice cultivars, and the flow from the wild relatives to the wild allies and their potential ecological risks. Meanwhile, a brief analysis was made on the environmental biosafety problems of GM rice. And a perspective on GM rice was given in the end of the article. The study will provide the reference for security application of transgenic rice.