A remote-controlled adjustable-speed screw drill for gas-drive hydraulic-motive during gas drilling is provided, including a piston speed control system, a motor assembly, a cardan shaft assembly and a transmission shaft assembly which are connected with each other from up to down in sequence. The motor assembly includes air inlets, a cam, air cylinders, pistons, a connecting rod, air outlets, liquid inlets, hydraulic cylinders, liquid check valves, a liquid storage chamber, liquid outlets, a liquid injecting chamber, a liquid injecting hole, an anti-drop cap, a rotor, a stator, and a motor assembly housing. The present invention utilizes the high-pressure gas injected by the gas drilling to drive the pistons to move back and forth at high-speed, so as to drive the incompressible liquid within the driving screw to achieve the self-circulating motion, and the screw rotor is driven to rotate by the liquid.