Objective：To analysis the clinical characteristics and high risk factors of incomplete abortion. In this study，the postoperative fertility is investigated. Method：55 cases of incomplete abortion that have been treated in Beijing obstetrics and Gynecology Hospital，Capital Medical University from October 2007 to October 2012 were investigated. At same time，we followed up these patients by telephone to collect information of their fertility status and contraceptive use. Result：The main clinical manifestations of incomplete abortion are abnormal vaginal bleeding in 42 cases（42/55，76.4 %）and abnormal menstruation in 13 cases（13/55，23.6 %）. Sonography is very useful to detect abnormal in the uterine cavity，but diagnosis of incomplete abortion requires the measurement of human chorionic gonadotropin（HCG）and postoperative pathology. The repeat curettage under the guide of B-sonograpy is effective. The main objective cause for incomplete abortion is excessive flexion of uterus，accounts for 23.6 %（13/55）. The main subjective factor is insufficient dilatation of cervix，accounts for 25.5 %（14/55）. The main complication of repeat curettage is intrauterine adhesions. The incidence is about 5.5 %（3/55）. There were 29 patients we could follow up. 17 cases have the history of pregnancy，11 cases have childbirth and 6 cases have artificial abortion to terminate pregnancy. Most of them use barrier contraceptive such as male condom to avoid unwanted pregnancy. Conclusion：The main clinical performance of incomplete abortion is abnormal vaginal bleeding after operation. The blood or urine HCG examination combined with ultrasonic examination can detect incomplete abortion timely. Repeat curettage under B- ultrasound guide is a effective treatment. The high risk factors of incomplete abortion include objective and subjective factors. The main objective factor is excessive flexion of uterus and the main subjective factor is insufficient dilatation of cervix. To reduce incidence of incomplete abortion，the operator need to carefully review the patient's medical history and physical examine to get the information of uterus. Ultrasonography in surgical operation is an effectively measurement to prevent incomplete evacuation especially those operations with high risk factors. Intrauterine adhesion should be in mind if the patient experience dysmenorrheal or amenorrhea. There are no signs of impairment of fertility after repeat evacuation. According to the use of contraceptive，more post abortion care about family planning is needed to help women choose high effective methods.