Cyclic stretch was exerted on ECV-304 cells (maximum strain 10%, 0.67 Hz). The morphological change and orientation adjustment of ECV-304 cells was analyzed by the computer image processing system. It was shown that the long axes of cells tend to be perpendicular to main strain direction after cyclic stretched for 3 h. The ratio of cellular long axis to short axis increase during the first 12 h of stretching, decrease during 12 h to 24 h, and then turned to be stabilized. Obvious relativi-ty existed between cell orientation adjustment and change of the ratio of short/long axis during the first 6 h of stretching. The intercept in the strain direction was shortened but in the direction vertical to strain was increased. It suggested that the cyclic stretch adjust the orientation of ECV-304 cells through the distinguishingly deforming course of cells in different direction, but not through rigid circumrotation or displacement of cells.