The invention provides a system and method for inspecting a three-dimensional sensor. According to the invention, a light source is controlled to emit a light of a known phase, and the known phase of the emitted light is altered by at least two known phase values. The three-dimensional sensor is driven in sensing the light reflected by the inspecting space to capture an image. In accordance with the captured image and the relative angle and the active brightness of each pixel thereof and the plurality of reference data, at least two quality data relative to the three-dimensional sensor are calculated.