The present invention relates to a bridge static load testing device and particularly relates to a simple-supported cast-in-place girder static load testing device. The device comprises jacks, gantry beams, vertical pulling rods, reaction frames and pier tight-holding devices. The gantry beams are above a test beam body. The jacks are between the gantry beams and the test beam body. The pier tight-holding devices are at the bottoms of piers at two ends of the test beam body. Two groups of reaction frames are at two sides of the test beam body, and two ends of each group of reaction frames are connected to two pier tight-holding devices respectively. Two ends of the gantry beams are provided with the vertical pulling rods and are connected to two groups of reaction frames. Since the existing piers are used to apply reaction force, a special test bed is not needed, the movement of the beams is not needed, the structure is simple, the assembly is convenient, and mobile operations can be carried out.