The invention relates to a method for quickly measuring content of bacteria in sewage of an oil field and finished oil, which mainly aims at solving the problems of lower measuring speed, inconvenience and inaccurate results in the prior art. The method for quickly measuring the content of bacteria in the sewage of the oil field and finished oil comprises a box body and bacteria enriching and nucleic acid molecule extracting equipment, wherein the bacteria enriching and nucleic acid molecule extracting equipment comprises a reagent tube placing position (1), a reagent tube placing position (4), a filtering membrane (2), an adsorbing layer (3), a reaction tank (5), a light source (6), a light filter (7), a light sensor (8) and at least four valves. By adopting the technical scheme, the method has the advantages that the technical problems are well solved, and the method can be used for measuring the content of bacteria in a liquid sample.