Abstract: The pump distribution and the transient three-dimensional temperature distribution in the medium of a diode pumped heat capacity laser are simulated by the ray tracing method and the finite element method. A diode face-pumped single chip Nd： GGG heat capacity laser is designed. The output power is 1.49kW with an optical-optical efficiency of 24.1%. When the working time is 1.2s, the experimental temperature at the center of surface of heat capacity laser is 81 ℃, and the simulation result is 78.1℃, which coincide well with each other.

Key words: heat capacity laser, diode-pumped, Nd：GGG, pump distributiontemperature distribution