The invention discloses a coking slop oil tank waste gas deodorization purifying device based on a chemical absorption method. The coking slop oil tank waste gas deodorization purifying device comprises a sewage tank, a coking slop oil tank, a buffer tank, a first ejector, an absorption agent circulating pipe, an air guide pipe, a first circulating tank, a pump I, a spraying head, a first absorption tower, a second absorption tower, a second ejector, a second circulating tank, a pump II and an exhaust cylinder, wherein waste gas of the coking slop oil tank and the sewage tank are concentrated to be guided out, and a great amount of oil gas and vapor, which are likely to condensate, are separated by virtue of the buffer tank, and then enter the absorption tower. Secondary cyclone plate towers are connected in series for the circular absorption, the secondary parallel-connection ejectors are installed in front of and behind the absorption towers to be used as power for guiding the gas, then an absorption agent and the waste gas are adequately mixed and absorbed again in the ejectors, and after the gas-liquid separation in the absorption agent circulating tank, the mixed liquid enters the exhaust cylinder to be discharged. The coking slop oil tank waste gas deodorization purifying device is a special petrochemical waste gas purifying device based on the chemical absorption method and has advantages of high reaction speed, high selectivity, good absorption effect, simple process, convenience in operation, safety, reliability and the like.