ObjectiveTo conduct risk assessment on clinical departments in a tertiary firstclass general hospital using ranksum ratio(RSR) method, screen out highrisk departments of healthcareassociated infection(HAI), and provide basis for developing HAI control strategies.MethodsRSR method was used to select 7 indexes for conducting a risk assessment on HAI control in clinical departments of a hospital in 2016, a high, medium and low risk rating was defined.ResultsIn 2016, neither complete good nor complete bad results appeared in the completion of each assessed index in 28 clinical departments. There was a high correlation between ranksum value and probability units(correlation coefficient r=0.944，P＜0.01, Linear regression equation RSR=-0.022+0.106Y）. Frequency analysis on RSR values in each department showed that results conformed to normal distribution ( KS test，P=0.873），most departments were at moderate risk, and only a few departments were at high or low risk. Six departments at high risk were neurology, intensive care unit, trauma hand surgery, neurosurgery, joint surgery, and respiratory medicine, RSR values were 0.7165, 0.6763, 0.6652, 0.6406, 0.6317, and 0.6205 respectively.ConclusionRSR method can be used to assess the risk of HAI in a real, objective, and scientific way, define key points of HAI prevention and control, improve resource allocation of high risk departments, and reduce incidence of HAI.