Objective To study the main mechanotransduction area and to estimate the overall shear deformation of rat osteoblasts in shear stress loading experiment based on data acquired from the in vitro rat osteoblast experimental, and to study the effects of four-point bending medium flow generated shear stress on cells. Methods Viscoelastic mechanics theory was used in the calculation process, the standard viscoelastic model was adopted for cells, and shear force on the cellular surface was simplified to be uniform. Results The cellular deformation caused by shear force was about one-tenth of that from tensile loading experiment which induced equivalent biological response. Conclusion In terms of mechanical stimulus induced biological responds, the mechanical transduction caused by cellular deformation in shear stress loading experiment is negligible, and the main transduction area is in the cellular membranes experiencing shear stress.