The utility model discloses a multifunctional dosing tank for a ground oil well, which comprises a medicine storage tank, a control box, a dosing flexible pipe and an oil delivery pipeline, wherein the medicine storage tank is connected with a high pressure plunger pump in the control box through a connection pipeline, and then connected onto the oil delivery pipeline through a throttle valve and a one-way valve of the dosing flexible pipe, and a wellbore gate is arranged at the connection part of the oil delivery pipeline and a wellbore; the top of the medicine storage tank is also provided with a dosing hole and a vent hole; a metering check valve is also arranged between the high pressure plunger pump in the control box and the throttle valve; and the dosing flexible pipe is connected onto the oil delivery pipeline through a reduction connector. Compared with the prior art, the multifunctional dosing tank has a simple structure, the liquid medicine continuously passes by a medicine outlet flexible pipe to be injected into the oil well through depending on potential energy under the action of self gravity, and the liquid medicine injection speed can be controlled by the throttle valve, and is convenient to adjust; and when the pressure is higher than the caliber pressure, the metering check valve is opened to safely work under the caliber pressure.