The invention discloses an X-nuclear channel broadband pre-amplifier of a high-field nuclear magnetic resonance spectrometer and relates to the pre-amplifier of the nuclear magnetic resonance spectrometer. The pre-amplifier is provided with a radio frequency switch control circuit, a radio frequency switch circuit, a direct current bias circuit, an amplification front-end protection circuit, a quarter-wavelength line, a low-noise amplifier circuit, an output matching network and a working state detection circuit. The output end of the radio frequency switch control circuit is connected with the input end of the radio frequency switch circuit and the input end of the amplification front-end protection circuit, the other input end of the amplification front-end protection circuit is externally connected with a port of the quarter-wavelength line, the other port of the quarter-wavelength line is externally connected with a probe, the input end of the low-noise amplifier circuit is connected with the output end of the amplification front-end protection circuit, the low-noise amplifier circuit is externally connected with the next-level part via the output matching network, the output end of the radio frequency switch circuit is externally connected with the probe, the working state detection circuit is connected with a switch signal generator, and the output end of the working state detection circuit is connected with the input end of the radio frequency switch control circuit.