The present invention relates to a toothbrush with dental plague display function. The toothbrush includes a toothbrush head, a toothbrush handle, a filter lens, a power device, an LED and a control circuit. Through the control circuit and the power device, the LED generates ultraviolet light that is radiated upon surfaces of teeth. The ultraviolet light is reflected by a mirror, and excessively reflected ultraviolet light on the surfaces of teeth is removed by the exclusive filter lens, and a user is allowed to easily observe dental plague displaying a fluorescence reaction on the surfaces of teeth.
