In surface grinding, the shape error is occurred by the thermal deformation of a ground workpiece. To finish the workpiece with high accuracy, it is necessary to understand the temperature distribution of the workpiece during grinding process. However there is no study to analyze the temperature distribution of a large workpiece during surface grinding process. In this study, an advanced simulation analysis method of the temperature distribution for a large workpiece was developed. In the developed simulation analysis method, the temperature distribution was calculated from the power consumption of the wheel motor. The power consumption can be obtained easily without any specialized equipment. To evaluate the developed simulation analysis method, in-process measurement of the temperature distribution of a large workpiece was also carried out. A large workpiece ground in this study weights about 1.3 tons. The temperature distribution was measured with thermistors mounted in many places of the ground workpiece. At the area close to the grinding surface, it was found that temperature rises immediately after the passage of grinding wheel with measuring the developed in-process measurement system. On the other hand, at the area far from the grinding point, temperature does not change quickly. The in-process measured temperature distribution agreed well with the simulated results.