Aiming　at　activated　sludge　process＇　characteristic,　a　modeling　algorithm　based　on　ANFIS　is　presented.　Using　water　quality　data　of　wastewater　treatment　plant　as　sample,　first,　principal　component　analysis　(PCA)　is　used　to　reduce　the　dimensionality　of　input　variables　and　to　remove　colinearity.　Second,　the　subtractive　clustering　is　used　to　build　initial　fuzzy　inference　system.　Then　ANFIS　is　adopted　to　build　activated　sludge　process　model.　Simulation　experiment　results　show　that　the　modeling　algorithm　based　on　ANFIS　is　effective,　compared　with　the　simulation　results,　the　fitting　ability　and　convergence　speed　of　the　PCA-subtractive　clustering-ANFIS　network　are　all　better　than　the　PCA-BP＇s,　and　it　is　much　more　suitable　as　activated　sludge　process　model.