Abstract: The discovery and verification of a new kind of laser, the random laser, as well as the mechanism whereby it produces coherent light are briefly described. This kind of laser has no cavity－mirrors. The function of the cavity－mirrors is borne by the photon－confinement effect in the disordered medium. Experiment has also shown how the confined photons are distributed in the medium. Microlasers around one micron in size can also be fabricated based on this mechanism.