The invention discloses a tunnel core drilling rig and a use method. The tunnel core drilling rig comprises a main engine, a control platform and a hydraulic pump station, wherein the hydraulic pump station is formed by combination and matching of a plurality of single pump stations. The main engine comprises a feeding device, a lifting frame, a base, a winch, a clamping holder, a gyrator and an auxiliary device. The feeding device, the lifting frame and the base are made of light materials. The feeding device is provided with a guide rail and a hydraulic cylinder. The lifting frame comprisesa fixing frame and a movable frame, and can realize the step-less expansion. The lifting frame further comprises a pulley frame, a pin shaft, a spring and a pulley. The pulley frame can automaticallyavoid a hole in the process of drilling up and down. Each of the single pump stations comprises a motor or diesel engine, a cooler, an oil filter, an air filter, a fuel tank and the like. According tothe tunnel core drilling rig and the use method, the problems of difficult removal caused by excessive weight of an existing tunnel drilling rig, limited construction space in narrow tunnel, and lowefficiency of lifting and lowering drilling tools and the like are solved.