Abstract: Based on service quality evaluation model and quality of service scale (SERVPERF), a service quality evaluation index system and the survey questionnaire are designed in this paper according to the core processes of 4S shop's after-service. A survey questionnaire was used to collect data. The right service quality evaluation system's weight was determined with entropy method, and a comprehensive evaluation model was built based on fuzzy evaluation for evaluating service quality of a 4S shop. The evaluation results were consistent with the fact. Through analyzing of initial data, some reasons, which influence the service quality, could be found and various proposals were put forward for improved service quality.