The disclosure provides a calibration assembly for a scan device. The calibration assembly includes a plurality of light-permeable plates and a reflection plate. The light-permeable plates are different in size, and the light-permeable plates are arranged along thicknesses directions thereof to form a step shape. The light-permeable plates define a plurality of light-permeable areas that respectively have different numbers of layers of the light-permeable plates inversely proportional to transmittances of the light-permeable areas. The light-permeable areas are configured to be permeable to a light having a predetermined frequency. The reflection plate is disposed at a side of one of the light-permeable plates in the thickness direction thereof. The reflection plate has a plurality of first holes having different sizes, and the reflection plate is configured to block the light having the predetermined frequency. The disclosure also provides a calibration system having the calibration assembly.