Abstract: Objective To study the effect of laser treatment on diabetic retinopathy（DR） after phacoemulsification and its mechanism. Methods Seventy-two eyes with diabetic retinopathy were treated with argon laser in 45 patients.The effect of laser treatment on diabetic retinopathy was observed. Results Two-three weeks after treatment with laser,diabetic retinopathy became stable,macular edema was disappeared or reduced in 76.9% of the patients,remained unchanged in 23.1% of the patients,visual acuity increased in 80.8% of the patients and decreased in 19.2% of the patients.One-three months after treatment with laser,developed diabetic retinopathy was observed in 16 eyes,macular edema was disappeared or mitigated 70.0% of the patients,remained unchanged 30.0% of the patients,visual acuity was increased in 75.0% of the patients and decreased in 25.0% of the patients. Conclusion Laser photocoagulation should be performed for diabetic retinopathy one month after phacoemulsification in order to control or delay the advance of diabetic retinopathy.