Aiming at the fact that the existing ground surface topography modeling method was only effective for a certain type of parts， a modeling method suitable for the processing of space curved parts was proposed. Based on the grinding process principle， the homogeneous transformation matrix between the grinding wheel and the surface part was established， and the three-dimensional equation of the abrasive particles was obtained. By proposing a surface area approximation solution algorithm， a prediction model was established. Taking gears and bearing inner sleeves as examples ， the maximum errors obtained are 11.338% and 18.91%，which has verified the validity and scientificity of the prediction model proposed.