Abstract: According to the transmission matrix theory, the resonator stability of end-pumped U-folded cavity Nd∶YVO4 solid-state laser was theoretical analyzed and numerically simulated. The stable region range of different cavity arm length and the oscillation spot at the center of crystal were obtained by changing several arm length of U cavity resonator and making comparison. A group of cavity parameters were obtained, which could keep the cavity steady at the high pump power and make oscillation spot perfect. Experiment was conducted with a group of cavity parameters. The experiment result shows that, resonator cavity work steadily and 21.6W output power is obtained under 100kHz repetition frequency and 60W pumped power. The results agree with the theoretical analysis.