An optical touch system includes a substrate, a glass module, two light sources, three reflective clothes, two image sensors and a processing module. The glass module is disposed at one side of the substrate. The two light sources are respectively disposed at two terminals of the glass module. The three reflective clothes are disposed on the edges of the substrate contiguously. A touch region is formed among the three reflective clothes and the glass module for reflecting the light emitted from the two light sources. The two image sensors are disposed respectively next to the two light sources and used for capturing images in the touch region. The processing module is used for determining whether a touch action is performed according to the images in the touch region.