OBJECTIVE To observe the clinical effect of argon laser photocoagulation on diabetic retinopathy (DR) in different stages. METHODS A total of 263 eyes in 170 patients with DR in different stages were photocoagulated using argon laser machine 2000. Thirty eyes in non-proliferative stage received focal photocoagulation, 156 pre-proliferative eyes received subtotal panretina photocoagulation, and 77 proliferative eyes were treated with panretinal photocoagulation. Additional focal or grid treatment was given for the eyes with localized or diffused macular edema. The visual acuity, eye fundus examination and retinal fluorescein angiography were carried out 3 months after the treatment and the results compared with the preoperative findings. RESULTS Improvement of visual acuity by at least one row on the visual chart was achieved in 92 eyes (35%), 144 eyes (55%) exhibited no changes, and 27 eyes (10%) deteriorated. Microaneurysm, retinal edema, exudates and fluorescence leakage were reduced in 89% of the eyes, with the rest eyes requiring additional treatment in the non-proliferative and pre-proliferative stages. For the retina in proliferative stage, neovascularization on the disc resolved completely in 67% eyes, whereas partially in 33% eyes which needed additional photocoagulation. The eyes with partial and complete resolution of macular edema accounted for 91% of the total eyes. Postoperative pre-retinal hemorrhage and vitreous hemorrhage occurred at the rates of 8% and 1%, respectively. CONCLUSIONS Argon laser therapy is effective for the eyes with DR in different stages, but produces better efficacy in non- and pre-proliferative stages than in proliferative stage. Follow-up and additional photocoagulation are necessary for the eyes in proliferative stage to ensure better outcome.