Provided are a centrifugal battery liquid injection mechanism and a liquid injection method thereof. The centrifugal battery liquid injection mechanism comprises a liquid injection device and a driving device, the liquid injection device is provided with a piston mechanism and a liquid outlet head capable of being opened and closed, and one end of the liquid injection device close to the liquid outlet head is further provided with a liquid injection port capable of being opened and closed; and the liquid injection port is used for injecting a wetting liquid into the liquid injection device. The liquid injection device is connected with a to-be-wetted device through the liquid outlet head, so as to inject the wetting liquid into the to-be-wetted device. The driving device is connected with the to-be-wetted device for driving the to-be-wetted device to move.