The invention discloses a projection display system based on full-color light-emitting diode matrixes. The projection display system comprises three light-emitting diode matrix modules, heat dissipation elements, light collection elements, a light mixing element and a projection element. The light-emitting diode matrix modules comprise the three light-emitting diode display matrixes with different wave lengths. The heat dissipation elements serve as accessories of the three light-emitting diode matrixes and are used for dissipating heat. The light collection elements are placed in front of optical paths of the light-emitting diode matrixes and used for collecting light and guiding the light into the light mixing element. The light mixing element is used for mixing the three types of light emitted by the three light-emitting diode matrixes to form a full-color image. The projection element is placed in front of the light mixing element and used for adjusting the image quality and the image size. The active light-emitting display system is realized, passive control elements in the traditional display technology are eliminated, and therefore the optical utilization rate is increased, and the power consumption of the display system is lowered.