The invention provides a pressure sensing fine adjuster and a pressure regulating and controlling method. The pressure sensing fine adjuster comprises a cylinder barrel, a piston, a push rod component, a connecting port, a driving device, a pressure detection device and a control device, wherein a containing cavity is formed in the cylinder barrel, the piston is positioned in the containing cavity, one end of the push rod component is connected with the piston, the connecting port is positioned at the second end of the cylinder barrel and communicates with the containing cavity, the driving device is connected with the push rod component, the pressure detection device communicates with the interior of a to-be-filled pipe, and the control device is connected with the pressure detection device and the driving device. The pressure sensing fine adjuster can be connected with the to-be-filled pipeline, when a heat transfer working medium is poured into the to-be-filled pipeline or after theheat transfer working medium is poured into the to-be-filled pipeline, the pressure sensing fine adjuster can adjust the pressure in the to-be-filled pipeline in real time, so that the pressure in the to-be-filled pipeline can be controlled at a preset pressure value, and then the filling precision is ensured.