Objective To verify the effects of the treatment of krypton yellow laser for diabetic macular edema.Methods A total of 430 eyes in 251 cases of diabetic focal macular edema, diffuse edema and cystoid edema were treated with krypton yellow laser photocoagulation. Those with focal macular edema underwent the focal photocoagulation, and those with diffuse edema and cystoid edema underwent the grid photocoagulation.The visual acuity examination, fundus fluoresec in angiography and colour photography of the fundus were performed before and every 3 or 4 months after the treatment.The changes of macular edema after the treatment were analysed.The follow-up duration was 3 to 23 months (with an average of 15.5 months). Results After laser focal photocoagulation in 186 eyes with focal macular edema, visual acuity was improved or maintained in 183 eyes (98.39% ). Edema disappeared completely or partially in 184 eyes (98.93%). After laser grid photocoagulation in 175 eyes with diffuse macular edema, visual acuity was improved or maintained in 163 eyes (93.14%). Edema disappeared completely or partially in 164 eyes (93.71%). After laser grid photocoagulation in 69 eyes with cystoid macular edema, visual acuity was improved or maintained in 59 eyes (85.5% ). Edema disappeared completely or partially in 64 eyes (92.75%).Conclusion The linchpin of the treatment of krypton yellow laser for diabetic macular edema lies in the insurance of the effective laser macules and the adaptability of selecting the proper parameter of laser according to the degree and scope of the macular edema and the visual acuity. (Chin J Ocul Fundus Dis，2003，19：14-17)