Abstract: In order to improve the stability of laser diode(LD) end-pumped Z-cavity solid-state lasers, take Nd∶GdVO₄ solid-state laser as an example. The influence of parameters like arm length and radius of curvature of the lens of the Z-shaped resonant cavity on the Gaussian beam was studied by numerical simulation, while considering the crystal thermal lensing effect. The relationship curves of the focal length of the crystal thermal lens with the variation of the pump power, the relationship curves of the stability of the resonant cavity with the variation of the focal length of the thermal lens, and the relationship curves of the Gaussian beam waist radius with the variation of the resonant cavity split arm length and the lens radius of curvature were obtained. The profile curves of the Gaussian beam were plotted. The results indicate that a suitable selection of the split-arm parameters of the Z-cavity can obtain a smaller beam waist size at the main plane of the crystal and the rear-end mirror, and the results of this study can provide a theoretical reference and basis for the construction of resonant cavities of Z-type solid-state lasers.