Abstract: Objective: To figure out the characteristics of annual medical expenditure for rural residents and its distribution among different population. Methods: After dealing with database of the 2014 new rural cooperative medical system, we got information about health care utilization of rural residents in Macheng county. Then we prescribe the clustering of medical expenditure using Lorenz curve and Gini index. At last, descriptive statistics and χ2 test were used to compare the characteristics and distribution of the annual medical expenditure among rural residents. Results: The costliest 5% patients account for approximately 68% of total health care spending. And the annual total expenditure is 16628 yuan per capita among high-cost population, while 108 yuan among low-cost population. The Gini index of medical expenditure for rural residents is 0.81. Among female and population over 45 years old, the proportion of high-cost population is higher than 5%. People living near provincial road, in flatlands or areas where the ability of township hospital is limited are more likely to expense higher medical costs. Conclusion: Clustering of medical expenditure for rural residents is remarkable, and the expenditure among high-cost, medium-cost and low-cost population is quite different. The elderly, female and people living in areas where the ability of township hospitals is limited are more likely to generate high medical costs.