This paper presents the exposure of endothelial cells to high glucose concentration combined with shear stress variety, which mimicking the heart beat cycle stimulates reactive oxygen species (ROS) overproduction and mitochondria damage, and further leads to increased cellular apoptosis. The apoptosis and necroses level is studied using real-time fluorescence microscopy with the measurement of yo-pro-1 iodide and propidium iodide dye. Results show the apoptosis rate matched well with the ROS overproduction and mitochondria damage rate and the study will further unclose the role of diabetes as a contributor to endothelial dysfunction and cardiovascular diseases. Copyright