Objective: To analyze the expense characteristics and influence factors of inpatients in CHS-DRG group of IC39 (joint surgery of hip, shoulder, knee, elbow and ankle except for replacement/revision surgery) and to explore expense control measures and grouping optimization strategies. Methods: The objects of this study from the patients with Beijing medical insurance who pilot IC39 group in a tertiary hospital featuring orthopedics in Beijing. The average expense and expense composition of objects with different characteristics were described. It conducted multivariate linear regression analysis to explore the influence factors of total hospitalization expenses, consumables expenses, and diagnosis expenses. Results: The consumables expenses in IC39 group accounted for the highest proportion of total hospitalization expenses (81.24%). Age, injury site and surgical method had statistically significant effects on total hospitalization expenses, consumables expenses, and diagnosis expenses. The type of injury only had a statistically significant effect on the diagnosis expenses. Conclusion: The consumables expenses were the key to control the expense of IC39 group. It gave priority to the centralized procurement of consumables with high price and large usage. The operation of joint repair and reconstruction, which should be formed in a DRG group separately, was more complicated and expensive. Diagnosis expense of old injuries was higher than that of fresh injuries, which was difficult to reflect the labor value of physician.