The utility model discloses an oil well hydrodynamic force ratio adjustment chemicals feeder, including last cylinder body, lower cylinder body, piston, connecting rod, the piston sets up at the upper cylinder half internally with upper cylinder half internal chamber share epicoele and cavity of resorption, piston bottom surface center is connected with the connecting rod, then the connecting rod stretches into down the chambers of the heart in the cylinder body, first check valve is connected to the connecting rod lower extreme, the check valve outer wall sets up the O -ring seal and seals cylinder body center intracavity wall under in, form the annular space in connecting rod and the lower cylinder body between the chambers of the heart wall, this annular space lower extreme and first check valve intercommunication, the upper end then feeds through the cavity of resorption of supreme cylinder body. The utility model discloses both reached the purpose that adds the medicine viscosity reduction, and realized again adding medicine ratio accurate control, and can indoorly operate. Use the guarantee to add medicine purpose and effect, worker occupation health etc. And as the theory, accomplish to take into account as far as possible comprehensively, bring into play the biggest effect of chemicals feeder.