The invention discloses a nitric acid pre-concentration method for waste acid concentration technology in production of dinitrotoluene, which comprises the steps of: leading waste acid coming from the washing process and/ or acid steam coming from the waste acid steam stripping process in a nitration system to enter a rectifying tower for vacuum rectification, then using a reboiler for vaporization, and obtaining products after concentration; sending the products obtained after concentration back into the nitration system; controlling the tower top temperature of the rectifying tower to be within the range of 73-78 DEG C and the tower bottom temperature of the rectifying tower to be within the range of 95-103 DEG C; leading gas phase arranged on the top of the rectifying tower to enter a first-stage condenser for condensation, sending first-stage condensate back into the top of the rectifying tower, and taking the first-stage condensate as reflux liquid, wherein the reflux ratio is 0.18-0.2; taking the rest stage condensate as waste water to be discharged; leading the tail gas of the first-stage condenser to enter a second-stage condenser for condensation, and sending all second-stage condensate back into the rectifying tower; and controlling the second-stage condensate to enter the rectifying tower at a rectifying section with the temperature of 80-82 DEG C. According to the nitric acid pre-concentration method, the content of nitric acid in the waste water can be reduced to less than 1%, so that the cost is greatly reduced, and the environmental pollution is reduced.