The invention discloses a fabricated large module semi-welded composite beam plate structure with plane truss temporary supports, and belongs to the technical field of structural engineering. The plane truss temporary supports are connected with beams through connecting plates and bolts to form a temporary whole body. Reinforcing mesh is arranged on the lower layer of a precast concrete layer andis paved on the temporary supports, and the precast concrete layer is poured after the reinforcing mesh is paved. The upper portion of the precast concrete layer is paved with reinforcing mesh pieceson the upper layer of a floor, and concrete is poured on the remaining floors to form a composite floor slab. After the fabricated large module composite beam slab structure with the plane truss temporary supports are fabricated and machined in a factory, the fabricated large module composite beam slab structure is transported to the site for hoisting. The upper portion of the precast concrete layer is paved with the reinforcing mesh pieces on the upper layer of the floor, and concrete is poured on the remaining floors to form the composite floor slab. After the floor maintenance is finished,the bolts are removed and the temporary supports are removed to complete the construction of the fabricated composite floor slab. According to the fabricated large module semi-welded composite beam slab structure with the plane truss temporary supports, the weight of the hoisting is reduced, and the fabricated accuracy and construction efficiency are improved.