The invention discloses a zero-leakage caustic soda liquid unloading device. The zero-leakage caustic soda liquid unloading device comprises a gas pump, a gas inflation pipe, a caustic soda liquid tank car, a caustic soda liquid unloading pipe and a caustic soda liquid storage tank, wherein the gas pump, the gas inflation pipe, the caustic soda liquid tank car, the caustic soda liquid unloading pipe and the caustic soda liquid storage tank are sequentially connected. A one-way valve and a flow sensor are arranged on the caustic soda liquid unloading pipe, the flow sensor is connected with an alarm apparatus through a wire, and the alarm apparatus is arranged at the caustic soda liquid storage tank. A caustic soda liquid feeding opening and a caustic soda liquid discharging opening are formed in the caustic soda liquid tank car. The caustic soda liquid feeding opening is connected with the gas inflation pipe through a sealing mechanism, and the caustic soda liquid discharging opening is connected with the caustic soda liquid unloading pipe. According to the zero-leakage caustic soda liquid unloading device, the caustic soda liquid unloading process is safe and reliable, and no residual liquid flows to the ground after caustic soda liquid unloading.