The invention aims to provide an optical test system which has the advantages that a clamp device and the test system can be applicable to modules to be tested in different sizes, the applicability of the clamp device is improved, and the cost of the clamp device in test cost is reduced. The optical test system provided by the embodiment of the invention comprises a machine platform, first guide rails, a first slide block and a second slide block, wherein the first guide rails are mounted on the machine platform and parallel to the surface of the machine platform; and the first slide block and the second slide block are arranged on the first guide rails, can slide on the first guide rails, and can clamp a module to be tested in a matching manner. The optical test system provided by the embodiment of the invention can be applicable to the modules to be tested in different length/width ratios, so that the applicability of the clamp device is improved; and clamp devices are not required for being designed and manufactured individually for all of the modules to be tested in different sizes any longer, so that the cost of the clamp device in the test cost is reduced.