The invention discloses a quantitative pump which comprises a driving motor, a quantitative meter assembly, a rotating shaft, a waist gear, a magnet, a pump body, an aluminum alloy impeller, a pump cover, a sealing cover, an induction cover, a signal source plate and an oil filtering assembly, wherein the quantitative meter assembly is fixedly installed on the end face of the top of the driving motor, and the pump cover is installed on one side of the driving motor in a connected mode; and the aluminum alloy impeller is mounted in the center of the inner side of the pump cover. According to the quantitative pump, the mechatronics technology is adopted, quantitative filling is achieved, the pump and the flow meter are integrated, efficiency is high, and the structure is compact; the waist gear is adopted, and the interior of the waist gear is of a hollow structure, so that the pushing force of the waist gear is reduced; the waist gear has the advantages of being high in sensitivity, small in size and low in operation sound, and diesel oil and other media with high viscosity can be accurately metered; and meanwhile, in the conveying process of the medium, particle impurities in the medium are effectively filtered out, and the quality of the medium is improved.