The invention belongs to the technical field of preparation of a catalyst used for synthesis of methanol and the technical field of chemistry, and more specifically relates to a processing method of NO exhaust gas in copper-zinc catalyst preparation processes. The processing method comprises following steps: NO exhaust gas generated in a metallic copper melting apparatus and a metallic zinc melting apparatus is cooled and is subjected to gas-liquid separation, and obtained tail gas is delivered into a NO absorption tower for tower internal circulating absorption; the tail gas is subjected to two-stage or multistage NO condensation compression absorption tower processing, and then is delivered into a diluted nitric acid storage tank; obtained diluted nitric acid is delivered into the metallic copper melting apparatus, the metallic zinc melting apparatus, and a copper-zinc mixed solution preparation apparatus as supplement of dissolving acid. Conversion ratio of NO exhaust gas is 95% or more, NO content in processes exhaust gas is less than 50ppm, and environmental protection is realized. Concentration of the diluted nitric acid obtained via the processing method is 20wt% or more, demands on acid used for a metal melting apparatus or copper-zinc mixed solution storage tank are satisfied, and resource saving and cost reduction are realized via cyclic utilization.