Objective To observe the variation of CD62p, the marker of platelet activation and platelet-leukocyte aggregates (PLA) in type 2 diabetes mellitus (T2DM) patients, analyze their sensitivity and specificity, and provide laboratory evidences for clinical diagnosis and treatment as well as prevention of complications for diabetes. Methods The percentage of platelet CD62p and the expressions of platelet-neutrophil aggregates (PNA), platelet-lymphocyte aggregates (PlyA) and platelet-monocyte aggregates (PMA) in the patients with T2DM were determined by flow cytometry (FCM). Results he percentage of CD62p, PNA, PLA, PMA in T2DM were significantly higher than that in healthy controls ［(13.38±8.56)% vs (3.41±1.09)%, (16.44±7.71)% vs (7.99±4.58)%, (13.57±7.30)% vs (8.29±5.57)%, (20.07±9.17)% vs (12.19±3.34)%］, (P<0.05). The percentage in T2DM patients with microangiopathy were significantly higher than that without microangiopathy ［(16.54±6.78)% vs (9.55±6.78)%，(16.18±7.63)% vs (13.93±6.83)%, (14.94±5.22)% vs (12.87±6.32)%, (24.65±9.97)% vs (16.67±7.20)%］, (P<0.05). The sensitivity and specificity of CD62p for diagnosis were 93.5% and 90.9%, PNA was 60.9% and 54.5%, PlyA 65.2% and 54.5%, PMA 78.3% and 68.2%, respectively. Conclusion CD62p, PNA, PLA, PMA should be indicators of microvascular injury in T2DM. The higher sensitivity and specificity of PMA and CD62p were found for diagnosis of T2DM, and CD62p may be the preferred marker.