The invention discloses a method for improving genetic conversion efficiency of Japanese lawngrass, whereof the main steps including: taking grass or juvenile spike in the lawn of Japanese lawngrass as primary receptor, inducing and choosing transgene direct receptor for stramineous, granular callus, and then culturing the callus of Japanese lawngrass by means of modified agrobacterium conversion method for 3 to 5 days, the GUS instant activity accessible to 400 to 550 locus ceruleus per gram callus. The converted callus would keep quite good regenerating ability, and the molecular detective result shows the conversion rate reaches more than 6 percents.