A multi-stage amplifier system based on high-power end-pumped two-segmented Nd:YVO4 is developed, which realizes the effective beam quality management in high-power laser. Because of the severe thermal effect caused by high-power end pumping, both the appropriate crystal and beam filling factor (the ratio of the laser beam radius to the pump beam radius) are important in the amplifier. The multi-segmented doped crystal is controlled in cooperation with beam filling factor to realize high output power and maintain good beam quality. To study the thermal effect in the end-pumped crystal, the temperature distribution of end-pumped single-segmented and two-segmented Nd:YVO4 are theoretically calculated. In the experiment, a probe laser is employed to measure the spherical aberration coefficient and the beam quality of the laser at the rear end of the two end-pumped crystals respectively, and the experimental results are in good agreement with the theoretical results. In the power amplification, a seed laser is employed in the experiment. The appropriate gain medium and beam filling factor are determined by considering the spherical aberration coefficient, beam quality and power extraction efficiency. Based on the reasonable layout of the power amplification for each stage amplifier, the multi-stage amplifier system outputs 280.2W picosecond laser with the beam quality factor of Mx2=1.28 and My2=1.32.