The　mechanism　of　compression　of　filter　cake　when　the　pressing　pressure　is　greater　than　the　filtering　pressure　is　analysed　in　this　paper.　The　equations　of　compression　and　hydraulic　pressure　distribution　are　derived　in　which　the　creep　effect　of　cake　is　taken　into　consideration.　The　hydraulic　pressure　distributions　in　cake　during　filtration　and　compression　is　detected.　The　experiments　were　carried　out　under　different　pressing　and　filtering　pressures,　and　the　experiment　data　show　good　agreement　with　the　equations　developed.