Laser assisted mechanical dressing and truing of diamond grinding wheel is a new truing and dressing method. The essential of the method lies in that laser irradiation makes deformation of diamond dresser material turn into ductile flow from brittle fracture, thereby improving the diamond wheel surface dressing and truing quality and reducing the wear of diamond dresser. A simulation model established by finite element methods using ANSYS software showed the distribution temperature field inside the diamond wheel. The actual temperature field under experimental condition is measured by infrared thermal imager (Model NEC TH7100WX/WV). The analyses show that the theoretical calculation results are consistent with those of experiments in the same experiment condition. The simulation model provides good effects on the quality forecast, parameter regulation and optimization in the process of truing and dressing diamond wheel. It also helps to avoid that high temperature make diamond grain graphitization or the temperature is not high enough to soften diamond wheel. The simulation model reduces the blindness to true and dress diamond wheel directly.