Objective：To study the risk factors of cervical insufficiency (CI). Design：Retrospective controlled study. Setting：First Hospital of Shanxi Medical University. Population：209 CI patients with a singleton pregnancy (CI group) and 348 patients randomly selected (control group). Methods and main outcome measures：All patients were required to have records of the whole pregnancy. The general conditions and pregnancy complications of the two groups were collected. A model of logistic regression and ROC curves were used. Results：Patients with a history of multiple pregnancies had a 17.51 times higher risk of CI than negative patients(OR=17.51, 95%CI: 2.16-141.85, P=0.007); patients who were pregnant by IVF-ET/ovulation induction had a 3.26 times higher risk of CI than negative patients(OR=3.26, 95%CI: 1.69-6.30, P<0.001); patients with gestational diabetes (GDM) or pregnancy with diabetes (PGDM) had a 2.88 times higher risk of CI than negative patients(OR=2.88, 95%CI：1.87-4.44, P<0.001); patients with PCOS had an 8.72 times higher risk of CI than negative patients (OR=8.72, 95%CI: 2.33- 32.64, P=0.001); and patients with uterine malformations had a 4.00 times higher risk of CI than negative patients(OR=4.00, 95%CI：1.07-14.97, P=0.040) . The ROC curve showed the combination of multiple indicators have a certain predictive ability for CI (AUC=0.728). Conclusions：Previous multiple pregnancy, IVF-ET/ovulation induction conception, diabetes mellitus (GDM or PGDM), uterine malformations, and PCOS are risk factors for the incidence of CI, and the combination of multiple indicators has some predictive ability for CI. Funding：None