Abstract: Objective To investigate the effect of pretreatment of anti-glaucoma on incidence of complications after cataract surgery in nanophthalmos. Methods It was a prospective cohort study. One hundred and ten cases with nanophthalmos who underwent phacoemulsification surgery from December 2012 to March 2016 in department of ophthalmology, Chinese PLA General Hospital were enrolled in this study. The patients were divided into with a history of anti-glaucomatous surgery group (group A, n=60) and without history of anti-glaucomatous surgery group (group B, n=50). Early (1 month after surgery) and late (1-3 months after surgery) complications were recorded. Results There was no significant difference in age, sex, cataract nucleus hardness and intraocular pressure between two groups before operation. The incidence of early complications including anterior inflammatory response, cystoid macular edema and uveal effusion in group A were higher than those in group B (44% vs 19%, P< 0.05), while, the intraocular pressure in group A was lower (12.45 mmHg vs 15.45 mmHg, P< 0.05). Conclusion Preoperative surgical intervention can effectively reduce the postoperative intraocular pressure in patients with nanophthalmos, however, the incidence of complications increase, such as macular edema in congenital microphthalmos with cataract.