Osteoblast is looked as a homogeneous isotropic and viscoelastic body which can’t be compressed. Using the standard linear model of viscoelasticity, the matrix form of the relationship between stress and strain can be achieved, so the finite element balance equation can be got through Lagrange equation. An example for bone tissues on porous media board under loading is calculated, the history of displacement, velocity and stress are obtained. Then the osteoblast cultured invitro can be numerically analyzed by computer program, and the deformation, the velocity and the stress of osteoblast can be calculated.