The assistant method of agrobacterium-mediated transformable efficiency which includes irradiation,callus,co-cultivation and negative pressure,is explored with the callus of Japanese lawngrass(Zoysia japonica Steud.).The results are as follow:2?J/kg of irradiation-dosage benefits the exaltation of transformable efficiency;1～2 months of callus proper is fit to the transformation;the transformable efficiency of the whole light shine to co-cultivation is higher than that of 16?h and 8?h photoperiod and the whole dark;the proper negative pressure,when agrobacterium and callus cultivated,could increase transformable frequency and survival rate of callus.