A modular structure wall of a high-temperature heating furnace including furnace wall main trusses and a furnace roof truss. Connecting I-beams are fixed on the bottom surface of the furnace roof truss, top clamping structures of hoisting outer screws are hooked with the bottoms of the connecting I-beams, the upper surfaces of ceramic fiber cotton modules are uniformly distributed with upwardly convex hoisting outer screws, and the ceramic fiber cotton modules are installed on the lower surface of the furnace roof truss through the hoisting outer screws. A gap is formed between the ceramic fiber cotton modules and the lower surfaces of the connecting I-beams, a ceramic fiber cotton felt is laid in the gap area between the ceramic fiber cotton modules and the lower surfaces of the connecting I-beams, and a furnace wall inner protective lining is fixedly installed on the lower surfaces of the ceramic fiber cotton modules.