The invention discloses a nitrogen tetroxide leakage collection device and method. The nitrogen tetroxide leakage collection device comprises a collection pipe, a collection container connected to thecollection pipe, an exhaust gas treatment module, a high negative pressure suction device and an electronic control module. The collection container and the exhaust gas treatment module are providedwith cooling systems. The upper part of the collection container is provided with a gas outlet. The gas outlet is connected to the negative pressure suction device through a gas suction pipe. The gassuction pipe between the collection container and the negative pressure suction device is provided with an absorption device for removing exhaust gas. Through being driven by the negative pressure suction device, the leaked nitrogen tetroxide liquid/gas and nitrogen dioxide are sucked into the inner collection container through the collection pipe, the gas-liquid mixture is subjected to gas-liquidseparation and cooling liquidation, the nitrogen tetroxide liquid is collected, and the tail gas is subjected to adsorption filtration so that toxic and hazardous substances in the tail gas are removed and thus collection efficiency is high and the environmental protection and conservation of resources are realized.