AIM: To evaluate the clinical effect of improved viscocanalostomy in patients with primary congenital glaucoma. METHODS: Retrospective analysis of improved viscocanalostomy was performed on 51 eyes of 42 patients with primary congenital glaucoma. The outcome evaluation included postoperative intraocular pressure(IOP), corneal diameter, cup/disc ratio and complications. All patients were followed up at week 1, month 1, 3, 6 and 12. RESULTS: The results revealed that postoperative IOP was decreased from (38.57±13.61)mmHg to (10.53±3.91)mmHg, (14.89±5.26)mmHg, (15.42±5.11)mmHg, (13.82±3.46)mmHg, (13.16±5.29)mmHg at follow-up time of 1 week, 1, 3, 6, 12 months (P<0.001). The postoperative corneal diameter was decreased significantly (P=0.002); The mean cup/dish ratio wasn’t significantly different (P=0.148) before and after the surgery, the cup/dish ratio of successful surgery was evidently decreased (preoperative 0.7±0.2, postoperative 0.6±0.3, P=0.007), but the complications like as unformed anterior chamber were not observed. The mean follow-up period was 12 months. CONCLUSION: Improved viscocanalostomy improves the clinical effects of the patients with primary congenital glaucoma, such as higher success rates, lower postoperative mean IOP and fewer complications.