Objective To investigate the effect of cyclic stretch on adhesion of vascular smooth muscle cells (VSMCs) with platelet-delivered microparticles (PMPs), and the role of PMPs in VSMC autophagy. Methods Using FX-5000T cyclic stretch loading system, cyclic stretch with the magnitude of 5% (mimics physiological mechanical stretch) or 15% (mimics pathological mechanical stretch) was subjected to VSMCs in vitro; using flow cytometry the adhesion of PMPs in VSMCs was detected. Immunofluorescence was used to detect the expression of autophagy microtubule associated protein light chain 3 (LC3) after 24 h stimulation with PMPs. Western blotting was used to detect the expression of autophagy related protein (Atg) in VSMCs after 24 h stimulation by PMPs. Results Compared with 5% cyclic stretch, 15% cyclic stretch significantly increased the adhesion ability of VSMCs with PMPs. Immunofluorescence snd western blotting revealed that PMPs stimulation significantly increased the expression of autophagy marker protein LC3 in VSMCs. Furthermore, the protein expressions ofAtg5, Atg7 and Atg12 (with 55 KDa molecular weight buth not 16 KDa) were all significantly increased in VSMCs stimulated with PMPs. Conclusion High cyclic stretch may enhance the autophagy of VSMCs by promoting the adhesion of PMPs, which subsequently increase the expressions of Atg5, Atg7, Atg12 and LC3. The investigation on mechanobiological mechanisms of VSMC autophagy induced by cyclic stretch may contribute to further understanding the vascular homeostasis and vascular remodeling, and may provide new potential targets for the clinical diagnosis, therapy, and evaluation of intimal injury during vascular reconstruction diseases.