Abstract: As an important role for "preterm birth syndrome", cervical incompetence cause a big impact to late miscarriage/preterm birth. Its aetiology remain unclear. By now, there is no diagnostic test for cervical incopetence, nor is there a universally accepted definition. The research of its aetiology contains congenital aetiology, such as deformity, race and genetic heritage, etc; acquired aetiology, such as surgery or birth trauma and other causes, such as inflammation, oxidative stress state, etc. The diagnosis of cervical insufficiency mainly from the history and clinical manifestation, diagnostic test and ultrasonic doppler. This review mainly discusses the aetiology and diagnostic criteria of cervical insufficiency, analysing the present research situation, and putting forward the new thoughts and suggestions.