Abstract: For the tone distortion problem occured when halftone image is printed，a tone self-compensation halftone model，which is based on Gamma transform and printer model，and a relevant modified error diffusion algorithm are proposed．With the adoption of feedback and self adapting control，the new model introduces a higher compensation precision than the present open-loop precompensation model．The modified error diffusion algorithm based on the new model will successfully compensate the dot gain and improve the quality of the printed image remarkably．