The invention discloses a paper mill wheat straw slurry black liquor treatment system which comprises a filter tank, a pre-sedimentation tank, an acid precipitation lignin tank, a sludge drying bed, a neutralization tank, a secondary filter tank, a heating tank and an anaerobic tank, wherein the filter tank is sequentially connected with the pre-sedimentation tank, acid precipitation lignin tank, neutralization tank, secondary filter tank, heating tank and anaerobic tank; the outlet ends of the neutralization tank and pre-sedimentation tank are respectively connected to the sludge drying bed through pipelines; baffle structures are adopted among the filter tank, pre-sedimentation tank, acid precipitation lignin tank, neutralization tank, secondary filter tank, heating tank and anaerobic tank, and the top of each tank is sealed with a steel plate; the upper part of the filter tank is provided with a water inlet; and the middle part of the bottom of the heating tank is provided with a water outlet. The paper mill wheat straw slurry black liquor treatment system is in the completely closed state in the treatment process to prevent other harmful reactions in the tanks. The system has the advantages of low manufacturing cost and favorable treatment effect, and completely satisfies the requirements for paper mill black liquor treatment.