The embodiment of the invention provides a positioning touch control method, device and system, and relates to the technical field of display. Positioning touch control over a projection display device can be achieved on the condition that a user does not need to operate computer equipment. The method comprises the steps that a first light sensor in the projection display device receives first light rays; if light intensity information of the first light rays is within the first light intensity range, the projection display device determines first coordinate information of the first light sensor on a projection screen; the projection display device sends the first coordinate information to the computer equipment, so that second coordinate information corresponding to the first coordinate information is determined by the computer equipment according to the first coordinate information and a coordinate mapping relationship between a prestored projection picture and a screen of the computer equipment, and touch control operation corresponding to the second coordinate information is executed in the computer equipment. The method can be applied to the projection display process.