The invention discloses a large-caliber bit fisher. The large-caliber bit fisher consists of a fishing coring sleeve installed on a drill rod, and a drilling tool connector, wherein the fishing coring sleeve adopts a hollow cylinder structure with an opening end; one end of the end surface of the fishing coring sleeve is installed on the outer circumference of the drill rod; a sleeve edge opening alloy cutter is arranged on the sleeve at the opening end of the cylinder; a combined structure of a cone and a cylinder is formed on the outer circumference of the drilling tool connector; a hollow structure is arranged in the drilling tool connector; screw threads are formed at the upper part of the hollow structure; a drill hook fixed through a hinge pin is arranged at the lower part of the hollow structure; the drilling tool connector is connected with the end surface of the drill rod through the screw threads; an open slot is formed in the cylinder of the drilling tool connector; the drill hook is movably connected by taking the hinge pin as a rotating shaft and taking the open slot and the lower part of the hollow structure as a rotating space. The large-caliber bit fisher has a simple structure, is easy to machine, assemble and store through integrated design, is light, safe to use, low in power requirements, and simple to operate and control, and can easily fish a drill at a pit bottom.