Screening marker genes play a crucial role in plant genetic transformation，and the development of safe and efficient screening marker genes is of great significance for transgenic crops.The potential of the phosphite dehydrogenase gene ptxD_Q with high catalytic activity as a screening marker gene for rice genetic transformation was comprehensively evaluated by means of tissue culture，nutrient solution screening and foliar spraying.The results showed that when ptxD_Q gene was used as a screening marker，the screening efficiency of resistant callus was about 44.37%-47.28%，significantly higher than that of the resistance genes including hygromycin and glufosinate.The positive transgenic seedlings can be screened by simply culturing transformed seedlings in the culture medium with phosphite as the only phosphorus source.In addition，a method for screening transgenic seedlings by foliar spraying of phosphite was established.Phosphite is less expensive and less polluting than the current antibiotic and herbicide screening systems.As a forward screening system，it has high screening efficiency and has potential value in studying transgenic crops and developing sustainable agriculture.