Objective: Medical therapy to prevent persistent ectopic pregnancy (PEP) after conservative laparoscopic operation was investigated. Methods:236 patients with ectopic pregnancy were divided into three groups according to the time of hospitalization. 83 cases were in group A, hyperosmolar glucose was injected into the fallopian tube lumen after laparoscopic salpingostomy. 81 cases were in group B, MTX was injected in the same way, 72 cases were in group C as control group. Serum β-HCG was tested for four times, before the operation, the first, third and a week after the operation respectively. Results:There were 6 patients of PEP in this study. One patient in group A, one patient in group B, the rest four patients in group C. The incidence of PEP was not statistically significant between group A and B( P>0. 05), while the difference was significant between group A and C ( P<0. 05). Serum β-HCG in three groups descended significantly in the first 24 hours after operation, but there were no differences among these groups. As for the descending of β-HCG in day 3 and 7, there was no difference between group A and B, but the difference was magnificent between group A and C( P < 0.05). Conclusions: Compared with the MTX, hyperosmolar glucose is an effective and safer method to prevent PEP.