Background: The recent studies have shown that sildenafil citrate can enhance estrogen-induced proliferation of the endometrium in infertile women. Objective: This study was aimed to investigate whether sildenafil citrate could affect pregnancy outcomes in infertile women receiving frozen-thawed embryo transfer (FET) after resection of intrauterine adhesions (IUAs). Materials and Methods: A total of 310 subjects who met the inclusion criteria were recruited and divided into the control group (group A) and the sildenafil citrate group (or the SC group, group B). The 2 groups were, respectively, divided into 2 subgroups based on the severity of reformed adhesions: (1) group A1 (with mild IUAs) and group A2 (with moderate to severe IUAs) and (2) group B1 (with mild IUAs) and group B2 (with moderate to severe IUAs). Therapeutic effects of sildenafil citrate on the cases were evaluated after resection of IUAs during FET cycles. Endometrial thickness, endometrial pattern, and pregnancy outcomes were evaluated and compared between the 2 groups. Results: There was no significant difference in the number of embryos transferred between the 2 groups. The endometrial thickness in group B (0.80 [0.68–0.90] cm) was significantly higher than that in group A (0.73 [0.35–0.80] cm). Besides, the biochemical pregnancy rate, clinical pregnancy rate, and live birth rate (LBR) were 71.60, 50.83, and 39.17% in group B, which were significantly higher than those in group A, namely, 57.36, 34.73, and 23.68%, respectively (p < 0.05). The univariate analysis and multivariate logistic regression showed that the LBR in either subgroups of group B after vaginal sildenafil treatment was significantly higher than that in the corresponding control group (p < 0.05). Conclusions: It was observed that the administration of sildenafil citrate during FET could effectively improve the poor endometrial conditions after FET following the resection of IUAs.