Objective To investigate the factors affecting uterine cavity repair and to provide a theoretical basis for the choice of expectant treatment for women with incomplete abortion．Methods From January to December 2021,534 patients with incomplete abortions were recruited at University of Hong Kong-Shenzhen Hospital,and their demographic characteristics and correlations from expulsion of the gestational sac to 3 weeks after medication abortion and after menstrual resumption were recorded,and the factors affecting uterine cavity repair in incomplete abortions were analyzed by multifactorial logistic regression．Results In 534 women,there were 240 cases of uterine cavity remnants after menstrual return,with a remnant rate of 44.9%;the results of multifactorial logistic regression analysis showed that BMI（OR=0.888,95% CI：0.808-0.975）,uterine position（OR=1.836,95% CI：1.139-2.958）,number of abortions（OR=2.258,95% CI：1.078-4.728）,length of vaginal bleeding（OR=0.344,95% CI：0.141-0.837）,maximum diameter of residuals（OR=1.061,95% CI：1.031-1.092）,and residual blood flow signal grade 2/3（OR=3.636,95% CI：1.790-7.394;OR=4.001,95%CI：1.561-10.256）were influential factors for uterine residuals．Conclusions High-risk factors for uterine residuals are posterior uterus,the maximum diameter of residuals,more than one abortion,grade 2 or higher residual blood flow signal,and the grade of blood flow signal had the greatest effect．BMI and duration of vaginal bleeding >3 weeks are protective factors for uterine residuals．