Scanning device and scanning method thereof

A scanning device, comprising:

• a scanning group comprising a line light source generating module and a scanning module, wherein the line light source generating module comprises a point light source, a light-guiding plate and a casing, a light emitted by the point light source along a first direction is converted into a line light source through the light-guiding plate disposed in the casing, the light emitted by the line light source along a second direction is emitted from an opening of the casing, the scanning module comprises a scan document region and a calibration region along the first direction, and the light reflected through a to-be-scanned document is received in the scan document region;
• a paper-feed roller disposed adjacent to the scanning group for driving the to-be-scanned document;
• a calibration portion disposed on the casing or the paper-feed roller, wherein the calibration portion corresponds to the calibration region of the scanning module and the reflected light is received in the calibration region through the calibration portion.