The invention relates to a high-strength composite drill bit, which comprises a drill pipe, a lower cutter body consisting of a lower cutter head and a lower cutter handle, an inner cutter body consisting of an inner cutter head and an inner cutter handle, blades, and an outer cutter body consisting of an outer cutter head and an outer cutter handle, wherein the lower cutter body is fixed at the lower end part of the drill pipe, the inner cutter body is fixed on the periphery surface at the lower part of the drill pipe, the number of the blades is 2-4, and the blades are uniformly fixed in a radiation form on the periphery surface at the lower part of the drill pipe and are positioned above the inner cutter body; the outer cutter body is fixed on the blades; the lower cutter head in the lower cutter body, the inner cutter head in the inner cutter body and the outer cutter head in the outer cutter body are respectively welded together with the lower cutter handle, the inner cutter handle and the outer cutter handle; the front ends of the lower cutter head, the inner cutter head and the outer cutter head are respectively provided with a lower cutting edge, an inner cutting edge and an outer cutting edge; and the installation directions of the lower cutter body, the inner cutter body and the outer cutter body are the rotation directions which make the lower cutter head, the inner cutter head and the outer cutter head arranged towards the drill pipe. The working efficiency of the drill bit is multiplied, the combination strength of the cutter head and the cutter handle is high, the wear of the cutter head and a rib is slowed down, and the construction quality is ensured.