A prefabricated thermal insulating composite panel with a corner, characterized in that it comprises two thermal insulating composite panel parts, each of said two thermal insulating composite panel parts comprises an internal main surface, an external main surface, and four side end surfaces, one side end surface of said four side end surfaces is formed to be inclined planes that incline relative to the internal main surface and the external main surface of said thermal insulating composite panel part, the two inclined planes have the same size and same inclination angle for mutual cooperation, the two thermal insulating composite panel parts are connected at the inclined planes through butt joint such that the two thermal insulating composite panel parts are disposed in two different planes, respectively, said two different planes intersect each other, and each thermal insulating composite panel part comprises:
- a core made of the thermal insulation panel;
- two reinforcing protective layers formed by cement-based or gypsum-based polymer-modified mortar, said core is disposed between said two reinforcing protective layers, and said two reinforcing protective layers are bonded with said core;
- a frame, said frame is disposed on three sides of the three side end surfaces other than the side end surface that is formed to have said inclined planes of said thermal insulating composite panel part of the core and is fastened to the core, inside each surface of the internal main surface and the external main surface of said prefabricated thermal insulating composite panel with a corner, said reinforcing protective layers cover said frame such that said frame is exposed only at said three side end surfaces of said prefabricated thermal insulating composite panel part of said prefabricated thermal insulating composite panel with a corner, said frame comprises two frame connection parts at the external side of said frame and disposed at the top and bottom of the frame, respectively, and an installation groove at the external side of said frame and disposed between said two frame connection parts, and said installation groove extends along the entire frame length.