Objective To assess the safety and efficiency of combination of micro incision phacoemulsification (PHACO) surgery and intravitreal ranibizumab injection in patients with cataract and diabetic macular edema. Methods The selected 68 patients (72 eyes) with age-related cataract and diabetic macular edema were randomly divided into two groups: the PHACO and intravitreal Ranibizumab injection (treatment group, 32 cases, 34 eyes), and only PHACO (control group, 36 cases, 38 eyes) in our hospital from July 2014 to November 2016. Preoperative and postoperative best corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP) were recorded. The time points included preoperative day, 1 week, 1 month, 3 months, 6 months and 12months after surgery. Results Postoperative BCVA during the follow-up period was higher than the initial BCVA in both groups (P<0.01). There was no statistically significant difference between both groups in BCVA at pre-operation and 1 week after surgery. In the treatment group, the postoperative BCVA was significantly higher than the control group at 1 month, 3 months, 6 months and 12months after operation. The mean CMT in the treatment group was lower than the control group in all the follow-up time. There was no statistically significant difference in IOP between two groups preoperatively and postoperatively during the follow-up period (P>0.05). Conclusion Additional intravitreal ranibizumab injection after PHACO surgery reduced macular edema and preserved this improvement in the mid-and-long term of BCVA.