After the introduction of the National Health Insurance, medical quality has become a commonly debated Subject. By the rapid growth in the standard of living, raises the expectation consumers have toward the quality of medical service they receive. This research tries to establish "the model of service quality" to improve service quality. The research discovered that outpatients consider most important is diagnosing equipment. The perception of outpatients toward service quality is lower than expected(negative gap), the gap is most large in waiting time. Its perception of service quality of outpatients is higher than that of the hospital staff(positive gap).