A new program based on the spatial light modulator(SLM) to modulate the phase and generate pseudothermal light is put forward. The influence of ghost imaging with different spatial light modulator pixel array arrangements is discussed. To improve the performance of pseudo-thermal light field, the design of spatial light modulator pixel array arrangement based on genetic algorithm is studied emphatically. The result shows that the spatial light modulator program overcomes the limitation of the ground glass program and the second- order correlation of the pseudo-thermal light produced by the spatial light modulator program is quite good. The light field generated by the spatial light modulator program can meet the needs of ghost imaging and the quality of the image is quite high. So the spatial light modulator program has an important reference for the new pseudo-thermal light source of ghost imaging.