Abstract: Objective:To investigate the sonographic features of corpus luteum of pregnancy and its relevant differential diagnosis with other lesions.Methods:The sonographic features of corpus luteum of pregnancy in 96 cases(including 32 cases with normal intrauterine pregnancy,30 cases with intrauterine pregnancy complicated with incomplete abortion and 34 cases with unruptured tubal pregnancy)were retrospectively analyzed,which was compared with tubal pregnancy.Results:Ninety-six corpus luteum of pregnancy and 34 ectopic pregnancy pieces were detected by ultrasound.The thick wall type sonogram luteal cysts were similar to the Dount sign of tubal pregnancy,which was surrounded by abundant blood flow and low resistivity characteristics.In contrast with tubal pregnancy,the corpus luteum of pregnancy was closely related to ovary,some follicles were detected arround it and the ring blood flow was from the ovary.Conclusions:The high detection rate of corpus luteum of pregnancy can be obtain by ultrasound.The correct recognition of the ultrasonographic changes of pregnancy corpus luteum can help to improve its differential diagnosis with other lesions.