Near a surface, the motion of a bacterial cell becomes different from the motion unaffected by any surface. In this paper, hydrodynamic interactions between flagellated bacteria and solid surfaces are analyzed based on the resistive force theory and the linearity of the Stokes equations, so as to establish a dynamical model for the bacteria in an infinite liquid. The swimming trajectories and the speed of the bacteria along a surface are numerically analyzed, and the results are compared with the experimental data, which verifies the validity of the model. Moreover, the relation among the flagellum geometrical parameters, the flagellar rotational rate and its swimming speed variation is calculated. All above researches provide a reference for the avoidance of surface effects in the motion control of a bio-mimetic swimming robot.