The invention discloses a combined highway and railway bridge isolation shed frame and a mounting method of wedge-shaped liners, and relates to maintenance engineering. The combined highway and railway bridge isolation shed frame comprises a main truss vertical rod, an outer bracket, an inner bracket, an opposite-pull device and at least one wedge-shaped liner. The main truss vertical rod comprises at least one groove. The outer bracket is fixed to one side of the main truss vertical rod. The inner bracket is opposite to the outer bracket and is fixed to the other side of the main truss vertical rod. The two ends of the opposite-pull device are connected with the outer bracket and the inner bracket respectively. Each wedge-shaped liner is composed of a fixed side bearing plate and a sliding side bearing plate opposite to the fixed side bearing plate. The two ends of each wedge-shaped liner abut against the two opposite inner side walls of the corresponding groove. Wedge-shaped faces are arranged on the contact end faces of the fixed side bearing plates and the sliding side bearing plates, and the sliding side bearing plates can move in the direction of the wedge-shaped faces. According to the combined highway and railway bridge isolation shed frame, railway line operation safety can be guaranteed, and deformation of the main truss vertical rod can be reduced; and the mounting and fixing process of the wedge-shaped liners in the combined highway and railway bridge isolation shed frame is simple.