By employing laser diodes end-pumped dual-longitudinal-modes Nd:YVO4 microchip laser as seed source, dual-end-pumped Nd:YVO4 traveling wave amplifier as power amplifier, a dual-frequency laser with larger frequency separation and high power output is obtained. In amplification process, spectral matching effects are analyzed. The results show that, with the increase of the seed light power, the overall magnification shows a decreasing trend, and the detail shows a wavy trend. Due to the limiting of amplifier gain bandwidth, the frequency separation of amplified signal is less than that of the seeds. When the pump currents of microchip and amplifier are 14.5 A and 40.0 A, respectively, the amplified output signal power is 2.38 W and the frequency separation is 47.7 GHz.