Optical touch system and positioning method thereof

The invention provides an optical touch system and a positioning method thereof. The optical touch system is used for positioning an object in a touch area and comprises at least one reflection element, at least one light guide module, an image sensor, a plurality of first light detectors and a processor, wherein the reflection elements are arranged on a side of the touch area, the light guide modules are arranged in the touch area and on one side adjacent to or opposite to the reflection elements and are used for generating light, the image sensor is used for capturing an image of the object, the first light detectors are arranged in the touch area and on one side adjacent to the image sensor and used for detecting the object to obtain first shading information, and the processor is used for computing a coordinate of the object according to the image of the object and the first shading information.