The utility model discloses a paper making wastewater treatment system, the system comprises a sewage pool, effluent water sump and grating de -dirt machine, grating de -dirt machine and equalizing basin intercommunication, equalizing basin and velocity of flow sorting pool intercommunication, centrifugal filter's liquid outlet and sedimentation tank intercommunication, heavy matter pond and sedimentation tank intercommunication, sedimentation tank and bological aerated filter intercommunication, bological aerated filter and AO pond intercommunication, AO pond and constructed wetland pond intercommunication, constructed wetland pond and ion exchanger intercommunication, ion exchanger and COD concentration detection device intercommunication, COD concentration detection device and clean water basin intercommunication. The utility model discloses a grating de -dirt machine gets rid of the large size floater and suspended solid, and velocity of flow sorting pool selects separately light impurity and heavy impurity, retrieves the lignin among the light impurity through acid out and centrifugation, heavy impurity and get into the sedimentation tank from postcordial filtrating and carryout preformed precipitate, reentrant bological aerated filter, AO pond and ion exchanger purify and further handle.