The invention provides a combined driving system of a construction elevator. The combined driving system comprises a driving rack and a driving unit installed on the driving rack; the driving rack comprises a driving plate and an upper rib plate, a lower rib plate, a left side plate and a right side plate which are fixed to the periphery of the driving plate through bolts; the driving unit is fixed to the driving plate through bolts, output shafts of the driving unit penetrate through the driving plate, a driving gear is installed at the end of each output shaft, and the driving gears drive a rack fixed to a guide rail to move through transition gears installed on the driving plate. According to the combined driving system, force is directly transmitted to a suspension cage by the driving unit through the driving plate, therefore, the transmitting links are reduced, and the driving efficiency is improved; the whole driving system adopts a machining and bolt connecting and fixing mode, therefore, the machining precision is improved, the equipment running stability is guaranteed, and the outstanding substantive features and significant progress are achieved.