A line scanning measurement system includes an illumination apparatus, a support, a telecentric optical element and a processor. The illumination apparatus is utilized for providing an extended polarized light beam. The support is utilized for mounting a sample, and the extended polarized light beam is directed at the sample. The telecentric optical element is utilized for directing a measurement light beam that has interacted with the sample toward a line scanning detector. The processor is utilized for obtaining the characteristic information of the sample in accordance with the signal measured by the line scanning detector.