An optical touch system including a touch surface, a plurality of image sensors, a calculation unit and an identification unit is provided. The touch surface is for interactive operation with an object. Each of the image sensors is configured to capture an image frame looking across the touch surface. The calculation unit is configured to calculate a coordinate of the object and an operating depth of the object corresponding to each of the image sensors according to the image frame. The identification unit is configured to increase a count value when the coordinate is within an operable range of one of the image sensors and the operating depth corresponding to the image sensor exceeds a depth threshold to accordingly perform hovering identification according to the count value.