摘要Background Getting medical treatment is still difficult and expensive in western China.Improving the equity of basic health services is one of the tasks of the new healthcare reform in China.This study aimed to analyze the parallel and vertical equity of health service utilization of urban residents and then find its influencing factors.Methods In August 2011,a household survey was conducted at 18 communities of Baoji City by multi-stage stratified random sampling.Based on the survey data,we calculated a concentration index of health service utilization for different income residents and a difference index of different ages.We then investigated the influencing factors of health service utilization by employing the Logistic regression model and log-linear regression model.Results The two-week morbidity rate of sampled residents was 19.43％,the morbidity rate of chronic diseases was 21.68％,and the required hospitalization rate after medical diagnosis was 11.36％.Among out-patient service utilization,the two-week out-patient rate,number of two-week out-patients,and out-patient expense had good parallel and vertical equity,while out-patient compensation expense had poor parallel and vertical equity.The inpatient service utilization,hospitalization rate,number of inpatients,days stayed in the hospital,and inpatient expense had good parallel equity,while inpatient compensation expense had poor parallel equity.While the hospitalization rate and number of inpatients had vertical equity,the days stayed in hospital,inpatient expense,and inpatient compensation expense had vertical inequity.Conclusions Urban residents' health was at a low level and there was not good health service utilization.There existed rather poor equity of out-patient compensation expense.The equity of inpatient service utilization was quite poor.Income difference and the type of medical insurance had great effects on the equity of health service utilization.