Abstract: Misplacement of intrauterine devices （IUDs） is one of the adverse complications of IUDs. Especially，locating outside of uterus is serious，even life-threatening. The risk factors of IUDs misplacement are the specific physiological status of uterus，abnormal shape，several diseases of uterus，as well as the absent experience of health workers. Clinical symptoms of IUDs misplacement are often unconspicuous and atypical. So，assistant examination is the main diagnosis method of misplaced IUDs. Sonography and ■ are convenient，low cost and nonintrusive，which can be used as the routine examination. The combination of sonography and x-ray can get better result. CT is an alternative method for its expensive cost. Both hysteroscope and laparoscope can make a definite diagnosis under direct vision， for removing the misplaced IUDs at the same time，but not for simple diagnosis. We discussed the diagnostic method，assistant examination，risk factors，clinical manifestation of misplaced IUDs，which are helpful for the service providers of primary family planning to diagnose accurately misplaced IUDs and to improve service level of reproductive health.

Key words: Intrauterine devices, Diagnosis, Ultrasonography, X-rays, Tomography, spiral computed, Laparoscopes, Hysteroscopes