A liquid crystal projection system includes a light source module, a light management module, an image signal module and a projection lens. The light source module provides an illumination light beam of first polarization state. The light management module includes a color separator for separating the illumination light beam into a first color light beam and a bichromatic light beam, first and second reflectors for respectively reflecting the first color light beam and the bichromatic light beam, a phase plate for converting the polarization of the bichromatic light beam, a first PBS for receiving the first color light beam, a second PBS for receiving the bichromatic light beam, and a dichroic prism for separating the bichromatic light beam into second and third color light beams. The image signal module includes three image modulation units for transforming the polarizations of the first, second and third color light beams and modulating them into image light beams carrying corresponding image signals. The projection lens projects the first, second and third color light beams carrying corresponding image signals from the second PBS to a screen.