Abstract: Objective To evaluate the medical work during"Operation Harmony -2010", summarize practical experience, find out problems, work out related countermeasures and to provide references for similar large-scale military operations other than war fay the Navy. Methods Investigations were made on medical professionals involved in"Operation Harmony -2010" and quantitative and qualitative analyses were made on the research results. Results Total satisfaction rate with the medical activities of the operation ranked the second best. The most unsatisfactory ranked in order were planning and organization, staffing and medical management. Conclusions"Operation Harmony -2010" was the first successful overseas medical relief activity ever performed by the Chinese Navy. It was a great step forward in many respects, such as service targets, service quality and quantity, as well as breadth and depth. The Navy has taken the initiative in the organization of such operations other than war. With the hospital ship as its platform, "Operation Harmony" series will be the chief important means to display the power of the Chinese Navy for a long period of time in the future. With further deepening of theoretical research and accumulation of practical experience, the organization and implementation of such operation will surely be more effective.