The invention is suitable for the technical field of image processing and provides a method and device for interaction projection. The method comprises the steps of predicting and obtaining a first projection image according to a projection image, and extracting hand foreground and a hand shadow according to the first projection image and a second projection image of the projection image captured by a camera; obtaining the positions of a fingertip and a fingertip shadow from the hand foreground and the hand shadow; and performing touch determination according to the positions of the fingertip and the fingertip shadow. According to the method for interaction projection, by utilizing the single ordinary camera, interactive hand movement extraction and touch determination can be implemented, the device is simple in structure and easy to implement, an expensive deep camera or a high-speed camera is not needed, and handheld human-computer interaction at a low cost can be implemented.