The invention discloses an ultrasonic dental scaler. The ultrasonic dental scaler comprises a handle, a member in the handle, a working tip in the front end of the handle, and a joint on the tail end of the handle, wherein a light source system is arranged on the head of the handle, a white-light lamp wick capable of emitting white light is arranged in the light source system, and a purple light lamp wick capable of emitting purple light and/or a blue light lamp wick capable of emitting blue light is/are also arranged in the light source system. According to the ultrasonic dental scaler, the purple light lamp wick and/or blue light lamp wick is/are additionally arranged in the light source system, thus realizing the detection on the calculus, scale and decayed teeth of teeth; the ultrasonic dental scaler not only can remove dental calculus and tooth stains, but also can conduct detection, thus realizing the multiple functions with one machine.