A displaying system having a function of sensing displaying properties includes a displaying panel, a controlling module, and an optical sensor. The displaying panel has a displaying surface which includes a presentation area and a function area. The function area is at a side of the displaying panel. The function area has a length in pixels longer than that of the presentation area. The controlling module is electrically connected to the displaying panel and the optical sensor and controls the displaying panel to display a presentation image displayed on the displaying area and an image for inspection on the function area. The optical sensor is disposed corresponding to the function area and senses the image for inspection to generate an inspection signal relative to the image for inspection. Thereby, the controlling module can further adjust displaying parameters of the displaying panel.