The exploitation of computer modelling in the study of cardiovascular disease has recently gained significant progress. In this study, the effect of microvessels stiffness on blood pressure and blood flow-induced wall shear stress (WSS) was analysed numerically. Three microvessels with diameters of 100, 200 and 300 microns and respectively media thicknesses of 10, 20 and 30 microns, were designed. Then for each model, three different elastic moduli of 0.4, 0.6 and 0.8 MPa were assigned. The blood flow within the microvessels was investigated using CFD analysis. A fluid-structure interaction (FSI) multiphysics analysis was performed to observe the effect of vascular stiffness on blood pressure and vice versa the effect of blood flow on the microvessel deformation. The result of the analysis showed that increasing the stiffness of a vessel increases blood pressure and WSS, and as well as causes a decrease in its deformability. The outcomes of this theoretical study shed more light on the understanding of cardiovascular diseases roots and origin, especially in micron-sized vessels..