Objective To evaluate the methods for improving diagnostic ratio of unruptured ectopic pregnancy with ultrasonography. Methods A total of 139 patients of small adnexal cysts with thick wall were predicted respectively with sonographic indexes. All patients (61 with unruptured ectopic pregnancy and 78 with small corpusluteum) were confirmed postoperatively or with long-term follow up, and the results were compared. Results The diagnostic sensitivity of with hyperecho or isoecho compared with endometrium, hyperecho compared with ovarian tissue, adnexal cyst without small follicle around was 86.89%, 93.44% and 96.72%, and the specificity of three predictors was 93.59%, 85.90% and 70.51%, respectively. Two sonographic indexes together had a sensitivity of 98.36% and a specificity of 94.87% for diagnosing ectopic pregnancy. Conclusion Observing the relation of adnexal cyst and ovarian and the echogenic of cyst wall are specific and sensitive for the diagnosis of ectopic pregnancy.