The　anisotropic　diffusion　model　plays　an　important　role　on　image　denoising　and　some　other　applications,　such　as　image　enhancement,　image　inpainting.　In　this　paper,　drawbacks　of　the　anisotropic　diffusion　model　and　the　fourth-order　PDE　model　are　discussed　and　examined.　In　order　to　compensate　these　drawbacks,　two　modified　diffusion　models　are　proposed　and　numerical　results　show　that　the　modified　models　produce　better　results　by　checking　against　the　PSNR　and　two　other　metrics.