The output performance characteristics of all-solid-state lasers end-pumped by a diode laser have been theoretically analyzed. Furthermore, the optic properties of laser crystals and nonlinear optical materials employed in all-solid-state lasers have been studied and compared by computer numerical simulation. The theoretical analysis and numerical simulation of optical parameters of laser-diode-end-pumped Nd:YVO4 and Nd:YAG lasers were carried out on the basis of theory of crystal level structure and rate equation. The good output properties of high efficiency Nd:YVO4 solid-state laser end-pumped by a diode laser are superior to of Nd:YAG compared in the same conditions. Therefore, Nd:YVO4 crystal has been demonstrated as an ideal laser gain medium in solid-state lasers with account of its high laser gain and low pump threshold, etc. The conversion efficiency of 40% of Nd:YVO4 crystal has been presented with an input pump power of 15W and a crystal length of 1mm. Furthermore, on the basis of phase-matching for the nonlinear optical crystal, the angular tuning curves of KTiOAsO4 and RbTiOAsO4 crystals for type-Ι and type-ΙΙ phase-matching have been simulated by computer, respectively. The tunable wavelengths of RbTiOAsO4 crystal from 1.320μm to 5.484μm in type-Ι, from 1.324μm to 5.424μm in type-ΙΙ were both wider than that of KTiOAsO4 crystal in the mid-infrared bandwidth. Therefore, RbTiOAsO4 crystal is an excellent nonlinear optical crystal of which tuning range is wider than that of KTiOAsO4 crystal in the mid-infrared band. As new crystals, the emerging of RTA and KTA has shown a promise for nonlinear frequency generation throughout the 1-5μm spectral region. Consequently, all-solid-state lasers capable of generating high quality near mid-infrared light have strong use value.