This work is mainly to study the effect of heavy ion irradiation on the damage of single layer MoS2.The number of layers of MoS2 prepared by CVD(chemical vapor deposition)method was determined by optical microscopy and Raman spectroscopy.The monolayer MoS2 prepared by CVD under high energy 209Bi ion irradiation was analyzed by Raman analysis and AFM observation.And the results are compared and analyzed before and after the beam irradiation of single layer MoS2 prepared by mechanical stripping method.