Objective To investigate the expression of p-HSP27 in vessel and vascular smooth muscle cells(VSMCs) exposed to different frequencies of cyclic tensile strain respectively, and to study its role in the migration of VSMCs.Methods Porcine common carotid arteries were cultured in a blood vessel organ-culture system under pulsatile flow for 24 hours.The frequencies of the flows studied were 0.5 Hz and 1.25 Hz.The mean pressure and flow rate were 15.996 kPa(120 mmHg) and 50 ml/min respectively.Human VSMCs were also subjected to 10 % tensile strain with two different frequencies, 0.5 Hz and 1.25 Hz, using a Flexercell Strain Unit for 12 hours.The expression of p-HSP27 in the vessel and VSMCs under different frequencies of strain was determined by Western blot.The change in VSMC migration after HSP27 RNAi was examined by Transwell under the two different frequencies of mechanical strains.Results The frequency 1.25 Hz activated the phosphatization of protein HSP27 more than the frequency of 0.5 Hz, in turn inhibited the migration of VSMCs.The migration of VSMCs significantly increased after HSP27 RNAi.Conclusion The results demonstrate that the biological frequency, 1.25 Hz, could inhibit the migration of VSMCs by activating phosphatization of protein HSP27 to maintain the biological structure and function of the vessel.