The invention relates to the technical field of automobiles, and particularly discloses an exhaust control method for a gas-driven urea pump system. The exhaust control method comprises the followingsteps of: S1, judging whether a key door is powered off or not, if so, entering step S2, and if not, entering step S3; S2, judging whether the gas pressure in a urea box is in a preset range and the environment temperature is higher than a preset temperature at the same time or not, if yes, not exhausting the urea box, and if not, exhausting the urea box; and S3, judging whether the rotating speedof an engine is zero, the current fuel injection quantity is zero, the vehicle speed is zero and the accelerator pedal opening degree is not smaller than a preset value within preset time at the sametime or not, if yes, exhausting the urea box, and if not, not exhausting the urea box. By means of the exhaust control method, the problems that the urea box is frequently exhausted, air consumptionof an air compressor is wasted, personnel safety cannot be guaranteed during manual exhaust, and threads of a urea box cover are abraded can be solved.