The invention provides a solar cell array unfolding device capable of being unfolded in large area, belonging to the technical field of aerospace equipment and equipment. The solar cell array unfolding device mainly consists of a master plate unfolding part and a side plate unfolding part, and the side plate unfolding part is arranged on master plates; the master plate unfolding part consists of tripods, master plates, master plate connecting hinges and truss rod synchronizing mechanisms, the master plate connecting hinges drive each master plate to be unfolded in the shape of Z, and scissors-shaped mechanisms are jointly formed by the truss rod synchronizing mechanisms and the master plates, so that each master plate can be synchronously unfolded; and the side plate unfolding part consists of side plates, servo motors, driving systems, screw rods, four-bar mechanisms, linear guide ways and side plate slide ways, wherein the servo motors drive the screw rods at two sides by the driving systems, and push the side plates to slide by the four-bar mechanisms, so that the side plates can be unfolded. The side plates are additionally arranged on the master plates, so that the solar cell paving area is enlarged; and the two symmetrical four-bar mechanisms push the side plates to unfold, so that the device is simple in structure, and high in reliability, thereby being suitable for the spacecraft which has high-power requirement.