The difference of grafting quality of Phaseolus vulgaris is that the stem grows normally, has a certain height and thickness, and has no quarantine diseases and insect pests. The basic conditions of excellent grafted seedlings are: the stem grows normally, with a certain height (1- 1.5m) and thickness (base diameter1-1.5cm); There are enough full buds or auxiliary tips in the plastic belt; Joint healing is good (smooth, no tumor, big feet or small feet), and the curvature of root neck is not too big; The root system is developed (the main root is more than 20 cm long, the lateral root is 8- 10, and it is more than 20 cm long without mechanical damage); No quarantine pests and diseases.