Extracellular　polymer　substance　(EPS)　in　activated　sludge　suspension　is　the　main　factor　of　membrane　pollution.　This　study　systematically　studied　the　fouling　behavior　and　mechanism　of　extracellular　polymer　substance　model　solutions　(BSA,　HA,　SA).　With　solutions　of　different　concentrations　(BSA,　HA,　SA)　as　the　feed　solution,　a　series　of　constant　cross-flow　filtration　experiments　were　conducted　using　0.1 μm　PAN　microfiltration　membrane.　The　transmembrane　pressure　(P),　fouling　resistance　(R),　and　effective　area　ratio　(A/A0)　were　used　to　describe　membrane　fouling.　The　results　show　that　the　fouling　mechanism　of　BSA　is　pore　blocking-cake　mechanism.　With　the　increase　of　concentration,　the　transmembrane　pressure　rises　faster,　the　effective　area　decreases　faster,　and　the　fouling　becomes　more　serious.　When　the　concentration　of　HA　is　less　than　1 g L−1,　the　fouling　mechanism　is　a　single　pore-blocking.　When　the　pore-blocking　is　completed,　the　available　area　ratio　and　resistance　no　longer　change.　At　high　concentration,　the　fouling　mechanism　is　pore　blocking-cake,　the　available　area　ratio　tends　to　be　stable,　and　the　resistance　increase　is　mainly　caused　by　the　cake.　When　SA　concentration　is　less　than　1 g L−1,　the　fouling　mechanism　is　a　single　pore-blocking　mechanism.　When　the　pore-blocking　is　completed,　the　effective　area　ratio　and　resistance　will　not　change.　The　fouling　mechanism　of　SA　at　high　concentration　is　pore　blocking-cake　mechanism.　The　high　concentration　causes　the　cake　to　appear　earlier.　This　study　provides　an　insight　for　further　understanding　the　fouling　behavior　and　mechanism　of　EPS　solution,　which　can　provide　theoretical　guidance　for　practical　application.　©　The　Author(s),　under　exclusive　license　to　Springer　Nature　Switzerland　AG　2024.