Objective To evaluate myocardial microvascular lesions in patients with type 2 diabetes mellitus(T2DM)by 2D-speckle tracking echocardiography(2D-STE)and myocardial contrast echocar-diography(MCE).Methods A total of 45 T2DM patients admitted to the Endocrine Department of The First Affiliated Hospital of Air Force Military Medical University from August to November 2022 were enrolled in this study.All the patients were divided into two groups:simple T2DM group(n=22)and T2DM with microvascular complication group(MIC,n=23).In addition,24 healthy subjects were included as normal control(NC)group.2D-STE obtained the global longitudinal strain(GLS)and global circumferential strain(GCS);MCE obtained the average acoustic intensity(A),perfusion slope(b)of left ventricular segment,then myocardial blood flow(Aβ)was calculated and compared between groups.Results Compared with NC group,GLS,GCS,β and Aβ were lower in T2DM and MIC group(P＜0.05).Among the parameters of 2D-STE and MCE,GLS and Aβ have high diagnostic performance(P＜0.05)and GCS and β have medium diagnostic performance(P＜0.05).ROC curve analysis showed that the early warning values of myocardial microcirculation disorders were-17.63%(GLS),-21.55%(GCS),0.845 s-1(β),7.045 dB/s(Aβ)in patients with T2DM.Conclusion The mechanical strain and perfusion of myocar-dium in T2DM patients have already decreased even no lesion was shown in the peripheral micro-vessels.2D-STE combined with MCE can assess the changes of myocardial elasticity and microcirculation in T2DM in real time,which is helpful for early clinical diagnosis of diabetes cardiomyopathy and intervention guidance.