A touch screen, a touch display device and a touch detection method are provided in the embodiments of the disclosure. In one embodiment, the touch screen includes a light guide element; a light source which is provided on a side of the light guide element to face inside of the light guide element, and configured to emit light towards the light guide element so as to be guided into the light guide element; and a plurality of detectors which are provided on at least one side of the light guide element to face inside of the light guide element, and configured to receive light from corresponding sides of the light guide element where the light exits, respectively.