The invention relates to an interactive projection system which comprises an image acquisition device, a control device, a protection device, an infrared signal generation device and a projection surface, wherein the projection device is used for projecting a calibration image to the projection surface; the image acquisition device is used for acquiring a calibrated projection image on the projection surface and sending the calibrated projection image to the control device to carry out calibration; the infrared signal generation device is used for emitting an infrared signal, wherein the infrared signal forms a light spot after encountering an obstacle; and the image acquisition device is further used for acquiring the image with the light spot and sending into the control device to calculate and further obtain the position of the acquired projection image located by the light spot in an original image which is preset in the control device before projection. The interactive projectionsystem has convenient use and low cost, and can be well applied in the field of man-machine interaction.