The invention discloses an injection molded base plate which comprises a base plate body. The injection molded base plate is characterized in that a butt joint rod is arranged on the upper surface of the base plate body, and a force transmission supporting leg is arranged at the corresponding position of the face, opposite to the face where the butt joint rod is arranged, of the base plate body in an injection molding mode. The butt joint rod serves as a main force bearing part of a component, force of the component is transmitted to one point of the base plate body in a concentrated mode, in this way, an excessively-large external force burden is brought to the base plate body to a great degree, although an injection molded product is good in integrality, the point force bearing capacity is not high, the force transmission supporting leg is arranged at the corresponding position of the face, opposite to the face where the butt joint rod is arranged, of the base plate body, point borne force acting on the base plate body can be effectively transmitted out, the point external force borne by the base plate body is reduced, the damage probability of the base plate body is lowered, and the quality of an overall assembled structure is guaranteed; in addition, due to the fact that the external force does not directly act on an injection molded plate face, the assembled overall structure can bear the larger external force, the aim of the injection molded base plate is accordingly achieved, and the injection molded base plate of the structure is suitable for filling bodies for cast-in-place hollow slabs.