Temperature variations affect pumping efficiency, spectroscopic properties of lasing ions, and physical parameters of the host material. A numerical model was developed for evaluation of multilevel solid-state lasers. The model accounts for atomic levels population variations during Q-switched pulse evolution and for temperature dependence of the lasing transition linewidth. Results of simulation of pulsed Nd:YAG laser are presented for various temperatures of the laser crystal. The results of the simulation are compared with experimental results obtained using a Neodymium:YAG laser which is Q-switched by crystalline and organic saturable absorbers. The observed behavior of the lasers is in good agreement with the theoretical prediction.