The invention discloses a method for manufacturing a T-shaped composite material reinforcement wallboard. A positioning mounting device is adopted for manufacturing the T-shaped composite material reinforcement wallboard; a second formation mold is adopted for preparing a soft mold, and a first formation mold is adopted for preparing a soft reinforcement rib mold with a positioning hole; the softmold, the soft reinforcement rib mold and soft panel molds are subjected to vulcanization formation; the soft panel molds are prepared in a combined mold, and reinforcement ribs are adopted for beinglaid to prepare L-shaped parts; firstly, a panel is placed in the combined mold, and then the two L-shaped parts are symmetrically arranged and combined to a T-shaped structure and mounted on the panel; then, the soft reinforcement rib mold is installed on a positioning support, and finally, the soft panel molds are installed at the two sides of a T-shaped part respectively. According to the method, positioning is conducted through the positioning support and the soft reinforcement rib mold, and accordingly the problem is solved that in the current condition of manufacturing the T-shaped composite material reinforcement wallboard, the reinforcement ribs are poor in position precision and irregular in straightness and appearance. The method has good practicability.