The utility model discloses a power amplifier of a high-precision traveling wave distance measurement calibrator, and the circuit of the power amplifier has symmetry, so that the amplifier has high linearity and large bandwidth in operation, and is suitable for designing a broadband high-power amplifier; according to the utility model, the push-pull amplifier is adopted to realize the high-power linear amplifier; common-source or common-emitter push-pull work of a balance MOSFET or a bipolar device is used respectively, and input impedance and output impedance are increased. For the same output level, the input impedance Zin and the output impedance Zout in the push-pull mode of operation are approximately four times higher than those in the parallel mode of operation thereof. Meanwhile, the input and output quality factors are kept unchanged because the real parts and imaginary parts of Zin and Zout are increased by 4 times.