The high-strength building formwork for supporting comprises a vertical formwork body and a reinforcing plate, a convex edge is arranged at the lower end of the vertical formwork body, a fixing ring is installed on the outer side of the vertical formwork body, a screw is installed in the middle of the front end of the fixing ring, a thread is arranged at the right end of the screw, a nut is installed at the thread, and a rotary connecting piece is installed in the middle of the rear end of the fixing ring. A plurality of supporting blocks are installed at the lower ends of the two sides of the fixing ring, supporting columns are installed at the lower ends of the supporting blocks, ground gripping teeth are arranged at the lower ends of the supporting columns, a transverse formwork is installed at the upper end of the vertical formwork, splicing edges are arranged at the lower ends of the two sides of the transverse formwork, and sealing formworks are installed at the two end openings of the transverse formwork; the reinforcing plates are arranged in the vertical formworks, the transverse formworks, the sealing formworks and the bottom formworks, during use, the reinforcing plates are beneficial to improving the strength and hardness of the vertical formworks, the transverse formworks, the sealing formworks and the bottom formworks, the situation that use is affected due to deformation and damage caused by extrusion and collision is avoided, and the strength and practicability of the formworks are effectively improved.