Objective：To quantitatively assess macular retinal thickness and display the features of macular morphology using stratus optical coherence tomography（OCT） in patients with type 2 diabetes mellitus. Methods：In a prospective study，OCT was performed in 120 eyes of 75 diabetic patients and 30 healthy eyes of normal control subjects. The diabetic patients were divided into three groups：non-diabetic retinopathy（NDR）, non-proliferative diabetic retinopathy（NPDR） and proliferative diabetic retinopathy（PDR）. We observed the different tomographic features of diabetic macula and measured macular thickness with the fast macular thickness mapping protocol of the ｓtratus OCT at the same time a day. For each eye，nine different sectors were analyzed（a foveal sector，four parafoveal sectors，and four extrafoveal sectors）. Results：There were statistically significant differences in foveal thickness and each of the nine areas among the control eyes，NPDR and PDR groups（P < 0.01）. But it had no significant differences between control eyes and NDR group. Visual acuity correlated with retinal thickness at the central fovea in diabetic retinopathy（ｒ =-0.69；P < 0.01）. Furthermore，OCT can identify sponge-like retinal swelling, cystoid macular edema（CME）, serous retinal detachment，hard exudates，epiretinal membranes（ERM） and other features in diabetic patients. Most eyes had more than one pathologic change ｉn these diabetes OCT demonstrated diabetic macular edema（DME） in 60.8% of eyes，hard exudates in 22.3% of eyes，ERM in 17.5% of eyes and normal foveal structure in 35.8% of eyes. Conclusion：OCT is a useful tool for observating macular thickening and structural changes in eyes with diabetic. OCT can facilitate the diagnosis, treatment and prognosis of diabetic patients，which is especially important in the early stages of diabetic maculopathy.