The development of high-power solid state laser technology is a course of struggling against the "waste heat" generated with lasering. The most critical issue for the development of high-power solid-state lasers is how to suppress the thermal effect on the beam quality under high-power operating conditions. To improve this adverse effect researchers invented heat capacity laser, thin-film laser, slab laser and fiber laser. These new designs of lasers based on novel form of gain medium combined with advanced heat dissipation technology have enhanced the output power to about one hundred kilowatts. However, the thermal properties of the solid state gain medium have become the critical bottleneck restricting further breakthroughs in laser power. Therefore, it is of great significance to explore the novel laser crystal materials with ultra-high thermal conductivity. This paper introduces the basic principles of the above four lasers and their research progress in high-power lasers. From the perspective of improving the thermal conductivity of gain medium materials, the existing methods and related results are analyzed and summarized. The research on ultra-high thermal conducting laser crystals and the development of high-power laser technology are also prospected.