Large-diameter rock core drill bit

A large-diameter rock core drill bit comprises a barrel and an upper cover plate, the upper cover plate is arranged on the inner wall of the barrel, the upper cover plate is connected to the upper portion of the upper cover plate, two rib plates are connected to the upper portion of the upper cover plate, the two rib plates are arranged in a crossed mode, a square-head box is arranged on the upper portion of the upper cover plate, and the square-head box is connected to the upper portion of the upper cover plate. The square-head box is arranged at the intersection position of the two rib plates, the lower portion of the cylinder is connected with a cutting ring, a cutting pick base is arranged on the lower portion of the cutting ring, cutting picks are installed in the cutting pick base, the cylinder is a long circular cylinder, and square grooves are formed in the lower portions of the two straight edges of the cylinder. At least two fillets are connected to the circular arc part of the side wall of the barr