AIM: To compare efficacy of coaxial microincisions (1.8 mm, 2.2 mm) and small incisions (3.0 mm) on phacoemulsification combined with trabeculectomy for primary angle-closure glaucoma (PACG) with cataract. METHODS: Ninety-six patients (96 eyes) with PACG and cataract were recruited and randomly divided into three groups between January 2015 and June 2017. Group A (3.0 mm incision), B (2.2 mm incision), and C (1.8 mm incision) comprised 30, 34 and 32 eyes respectively. All cases were treated with clear corneal incision phacoemulsification combined with trabeculectomy. Data including best corrected visual acuity (BCVA), corneal astigmatism, corneal endothelial cell counts (CECC), intraocular pressure (IOP), and complications were collected before the operation, and at postoperative 1d, 1 and 3mo. RESULTS: All the patients were successfully treated with surgery. The BCVA of groups B and C were significantly improved as compared to group A at postoperative 1d, 1 and 3mo (all P<0.05), but there was no difference between groups B and C at each time interval (all P>0.05). The corneal astigmatism of group A was statistically higher than that of group B (P=0.026); corneal astigmatism of group B was statistically higher than that of group C at postoperative 1d (P=0.006). The corneal astigmatism of group A at postoperative 3mo was significantly higher than that before operation (P=0.003). At postoperative 1 and 3mo, corneal astigmatism of groups B and C were significantly lower than that of group A (all P<0.05). The CECC in group B was significantly higher than that of group A (P=0.020), and CECC in group C was significantly higher than that of group B (P=0.034) at postoperative 1d. At postoperative 1 and 3mo, CECC of groups B and C were significantly higher than that of group A (all P<0.05). In each group, postoperative mean IOP at each time interval was significantly lower than preoperative IOP (all P<0.05). CONCLUSION: Coaxial microincision phacoemulsification combined with trabeculectomy for PACG with cataract has better curative efficacy in reducing postoperative corneal astigmatism and corneal endothelial cell injury than traditional small incision combined surgery, and the 1.8 mm microincision has better curative efficacy than 2.2 mm microincision in the early postoperative period.