In order to suppress the speckle effect of target surface induced by laser illumination, and to increase the image quality of laser active imaging, the multibeams illumination technology was adopted and its effect on rejection of returning wave speckle was investigated theoretically and experimentally. The splitting illumination model of multibeams was established. The speckle suppression principle of multibeams illumination in entire speckle superposed field and partly speckle superposed field was analyzed. On the basic of the principle and theory model, the simulation experiment system was set up, where the returning speckle contrast of single beam and multibeams illuminated on three different roughness targets with different splitting ways was evaluated by adjusting the energy distribution. The experiment result indicates that the contrast of homenergic four beam can be reduced to half of that of single beam, which complies to the theory analysis and proof the feasibility of speckle rejection using multibeams illumination.