Abstract: Objective: To analyze the out-patients satisfaction,and to explore ways to better service by combining Hospital Customers Satisfaction Index model (HCSI) model and gap analysis. Methods: We designed a questionnair according HCSI model and gap analysis and conducted the survey among 3618 out-patients in a teriary Grade A hospital.We discussed the improving strategies by gap analysis. Results: The average score of out-patients' satisfaction was 8.48.Patients had high expectation and loyalty, and they were satisfied with the diagosis and treatment skills. By gap analysis,waiting time and additional service were the two dimensions with biggest gap. Conclusion: HCSI model and gap analysis are useful tools to find out service gaps and could provide uselful improvement suggestions to better hospital management and service.