The utility model provides a spent acid processing system, including storage portion, solid -liquid separation portion and allotment portion, wherein, the discharge gate of storage portion pass through the pipeline with the pan feeding mouth of solid -liquid separation portion is connected, the liquid outlet of solid -liquid separation portion pass through the pipeline with allotment portion connects, allotment portion is including adjusting bucket, water pitcher and acidizing fluid jar, the water pitcher with the acidizing fluid jar respectively with it connects to adjust the bucket. The spent acid that contains impurity and gelinite passes through the utility model discloses handle, obtain meet the standard's acidizing fluid, suitably adjust proportion again, mix according to certain proportion with new dilute sulfuric acid, directly add new battery during the production of next liquid feeding, do not reduce through the experiment battery performance, accord with the standard of battery completely, realized the effect of energy -conserving, consumption reduction, reduction of discharging.