Abstract To make completion selection mathematically, a comprehensive well completion system evaluation system was established including 3-class, 14-indicator including technical, managerial, economic, and risk indicators. Mutation theory was first introduced to determine the weights. Combined with fuzzy mathematics, the fuzzy membership function mutation was developed to act as the evaluation way. After 3-class judgment, the completion method with the maximum value of membership function was preferred. The method was applied to the East China region and targeted in 10 directional and 2 horizontal wells. Results showed that the comprehensive model is of high accuracy.