A sensing system includes a complex reflector and an image sensor, in which the complex reflector is disposed on one side of a flat panel. The complex reflector includes a first section and a second section which are stacked, in which the first section provides a mirror image and a real image, and the second section provides a real image. The image sensor is used to capture an image generated by an object when touching a surface of the flat panel, and in the image captured by the image sensor, the object simultaneously generates a first object image in an image region corresponding to the second section and an image region corresponding to the first section, and generates a second object image in the image region corresponding to the first section.