To improve the energy efficiency of the inertial confined fusion (ICF) high\|power laser system and sufficiently use the optical energy, it is important to convert Gaussian laser beam into uniform beam. From the Jones matrix of spheric lenses, the intensity transmittance distribution of birefringent lenses spatial beam shaping system has been analyzed in detail by optical transmission matrix. The shaping effect has been numerically simulated. The choice of the parameters of birefringent lenses is discussed. The factors, which will influence the shaping effect, such as the fabrication error of center thickness, have also been analyzed. In the experiment, the uniform laser beam is obtained. In the ninth beamline of “Shenguang-Ⅱ” device, the static beam filling factor of near field is improved from 66% to 80%.