Based on the rigorous coupled wave analysis method, the subwavelength grating wavefront control method was analyzed, three subwavelength grating structures with the function of convex lens, cone lens and blazed grating were designed. These devices achieve good focus and blazing effect. By calculating the grating transmittance at different grating thickness, grating teeth and grating groove width, the transmittances of the three wavefront manipulation devices are all above 97% after selecting the combination of suitable grating parameters. Compared the performance of silicon-based planar structural devices with conventional structural devices, the lens and the cone lens of the planar structure, the Full Width at High Maximum of the focal spot is approximately equal to that of the conventional lens and cone lens, but the peak intensity is increased to 1.64 and 2.35 times. The peak intensity of the planar relative to the conventional blazed grating is increased to 3.77 times.