Comparative study was carried out on the error diffusion algorithm based on weight perturbation and conventional error diffusion algorithm. The result indicated that the effect of the error diffusion algorithm with four perturbation weights is little batter than Floyed-Steinberg; this algorithm reduces the pseudo outline and sharpens the image edge to some extent, but the pseudo outline and the hysteresis phenomenon still exist. Uniform gray patch with different level was output by the method; radial average power spectrum and anisotropy of the output result was analyzed. The effects of objective assessment and subjective assessment were compared and the relation among halftone output quality, radial average power spectrum and symmetry was obtained. The research direction of halftone algorithm to improve halftone output quality was put forward.