OBJECTIVES: Little research concerning to the effect of co-morbidity on Health Service Utilization was conducted in field of General Practice. We aim to explore the effect of common chronic diseases on the Health Service UtilizationG METHODS: Cross-sectional design was conducted. 750 Sample of patients was obtained via three stages of cluster sampling. Each patient was asked whether or not he or she contracted following eight common chronic diseases diagnosed by doctor, i.e., hypertension, diabetes, heart attack of any category, apoplexy, asthma or other respiratory disease (COPD), chronic arthritis, mental disease and other disease lasting over four weeks. Our research focuses on the relation between common chronic diseases and Health Service Utilization (monthly consultation rate, annual consultation rate and annual hospitalization rate). RESULTS: Our research has shown that Health Service Utilization of each chronic disease is all higher than reference group. The overall number of chronic diseases has the linear relation with annual consultation rate, monthly consultation rate and annual hospitalization rate separately. Meanwhile, increasing one type of chronic disease leads to adding additional 8.3 annual consultation rat; the OR value of annual hospitalization rate is 1.786 which hints that increase one type of chronic diseases will induce more 78.6% relative risk of possible hospitalization rate. Furthermore, the other seven types of chronic diseases, except for apoplexy, have a positive linear relation with annual consultation rate; diabetes, cardiopathy and apoplexy have respectively positive linear relation with annual hospitalization rate. CONCLUSION: Our systematical approach addressed the scarcity that most researches in China only focus on single disease, especially in the field of General Practice Research. Our research supports the assumption that common chronic diseases can be taken as the predicting factor for risk adjustment model and can predict health services utilization.