An infrared touch screen, comprising: a touch detecting region; a plurality of edges comprising at least a first edge and a second edge, wherein said first edge and said second edge are opposite to each other, said first edge having infrared emitters and infrared receivers fixed thereon, and said second edge having infrared emitters and infrared receivers thereon; and a phase managing mechanism configured to control a phase alternation of said infrared touch screen which has a plurality of phases having at least a first phase and a second phase; wherein said phase managing mechanism controls the infrared emitters fixed on said first edge and the infrared receivers fixed on said second edge to scan said touch detecting region in said first phase; and said phase managing mechanism controls the infrared receivers fixed on said first edge and the infrared emitters fixed on said second edge to scan said touch detecting region in said second phase, the infrared touch screen is characterized in that a standard ambient light intensity (m) is preset in said phase managing mechanism; in said first phase, if the intensity of the ambient light received in said infrared receivers fixed on said second edge is not larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to maintain the first phase; if the intensity of the ambient light received in said infrared receivers fixed on said second edge is larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to terminate the first phase and enter into the second phase; and in said second phase, if the intensity of the ambient light received in said infrared receivers fixed on said first edge is not larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to maintain the second phase; if the intensity of the ambient light received in said infrared receivers fixed on said first edge is larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to terminate the second phase and enter into the first phase. a touch detecting region; a plurality of edges comprising at least a first edge and a second edge, wherein said first edge and said second edge are opposite to each other, said first edge having infrared emitters and infrared receivers fixed thereon, and said second edge having infrared emitters and infrared receivers thereon; and a phase managing mechanism configured to control a phase alternation of said infrared touch screen which has a plurality of phases having at least a first phase and a second phase; wherein said phase managing mechanism controls the infrared emitters fixed on said first edge and the infrared receivers fixed on said second edge to scan said touch detecting region in said first phase; and said phase managing mechanism controls the infrared receivers fixed on said first edge and the infrared emitters fixed on said second edge to scan said touch detecting region in said second phase, the infrared touch screen is characterized in that a standard ambient light intensity (m) is preset in said phase managing mechanism; in said first phase, if the intensity of the ambient light received in said infrared receivers fixed on said second edge is not larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to maintain the first phase; if the intensity of the ambient light received in said infrared receivers fixed on said second edge is larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to terminate the first phase and enter into the second phase; and in said second phase, if the intensity of the ambient light received in said infrared receivers fixed on said first edge is not larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to maintain the second phase; if the intensity of the ambient light received in said infrared receivers fixed on said first edge is larger than said standard ambient light intensity (m), said phase managing mechanism controls said infrared touch screen to terminate the second phase and enter into the first phase.