The invention discloses a combined mold plate support system, and belongs to the technical field of building construction. The combined mold plate support system comprises a beam bottom mold plate support device (3) and a plate bottom mold plate support device, wherein the beam bottom mold plate support device (3) is positioned on the lower side of a beam (2); the plate bottom mold plate support device is positioned on the lower side of a floor (1); the beam bottom mold plate support device (3) and the plate bottom mold plate support device are independently arranged; the beam bottom mold plate support device (3) comprises beam bottom mold plate support units (11), beam side mold plate support units (12) and support rods; two beam side mold plate support units (12) are arranged o the beam bottom mold plate support units (11) at intervals; the support rods are vertically fixed at the middle parts of the lower sides of the beam bottom mold plate support units (11); and a fixing rack (16) is fixedly connected with the lower parts of the support rods. The combined mold plate support system is reasonable in stress and convenient to operate, the construction quality of a mold plate and concrete can be improved, and the time and labor are saved.