In　this　study,　error　function　was　used　to　analyze　the　membrane　fouling　behavior　(flux　decay)　for　bovine　serum　album　(BSA)　solution　in　dead-end　mode　and　for　kaolin　suspension　in　cross-flow　mode　under　constant　pressure.　The　results　showed　that　the　predictions　of　error　function　had　good　agreements　with　experimental　data　both　in　dead-end　mode　and　cross-flow　mode.　Meanwhile,　both　higher　concentration　and　higher　TMP　could　accelerate　the　membrane　fouling　rate.　In　addition,　the　parameter　k　in　error　function　decreased　with　the　increase　of　concentration　or　TMP.　Thus,　smaller　parameter　k　represented　more　serious　membrane　fouling.