The invention discloses a sewage treatment foundation technology of the pulping and papermaking industry. The sewage treatment foundation technology comprises the steps of front auxiliary, a first-stage sewage treatment core technology, middle auxiliary, second-stage sewage treatment core technology and rear auxiliary; in the whole technology process, controlling is performed on the basis of pH values of a water body at all technological points, and various parameters can be set according to the requirements of feed water and yielding water indexes. According to the sewage treatment foundation technology of the pulping and papermaking industry, it can be guaranteed that an ion fractionation medicament has the following representative characteristics and advantages in practical application that the dosage is little (10-300 g per ton of water), the medicaments are directly dosed in a solid state without needing to be diluted, sewage is treated in real time without storage (the reaction time is 3-15 minutes), and the removing rate of water body contents is more than 80%; in addition, the national various sewage treatment discharge indexes are followed and met, treated water is colorless and free of abnormal odor and secondary harmful chemical substances, and sludge generated through flocculation is low in water content (smaller than 35%), odorless, not sticky and the like.