Based on the generation, harmfulness and solution of thermal effects of lasers, different kinds of lasers are illustrated in detail from the perspective of their principle and recent progress on high power, including thin disk lasers, heat capacity lasers, slab lasers and fiber lasers. As practical application on laser weapons, projects and progresses of laser weapons are classified. The development trend of high power solid-state lasers is proposed, which is low cost for operation and maintenance, compact structure and unmanned aerial vehicle (UAV) loading. Furthermore, the development advantage and the tendency of composite lasers are addressed.