As laser diode-end-pumped laser amplifier of moderate aperture can realize repeated-rate high energy output and good beam quality, it is paid more attention as inertial fusion energy (IFE) driver and directional energy weapon (DEW). Ndglass as laser medium has many advantages, such as easy to manufacture, high storage energy, moderate emission cross section. However, its thermal conductivity is low and thermal effect is serious. Therefore, through analysis for the performance features of laser diode-end-pumped Ndglass laser amplifier, a ray tracing and finite element thermal model is established, and 3D and transient distributions of temperature and thermal stress in Nd:glass are simulated. The impacts of pump power, cooling parameter and repeat rate are mentioned, the mechanism of thermal fracture is also analyzed. The results are helpful of designing laser diode-end-pumped repeated-rate Nd∶glass laser amplifier.