The mid-infrared lasers are of important application values and development prospect in many areas such as spectroscopy,remote sensing,medicine,environment monitoring and military et al,and thus become a research hotspot of world common interest.In the paper it is introduced that the progress on different mid- infrared optical parametric oscillators（MIR-OPOs）and their pump sources,and then the advancement on mid-infrared unipolar quantum cascade laser（QCL）.