To address the issue of decreased signal-to-noise ratio in Doppler signals when using a laser Doppler velocimeter for high-speed carrier velocity measurements, this study analyzes the impact of pre-amplifier circuit output noise on Doppler signal quality. Theoretical analysis and simulation results indicate that the noise gain peak in the pre-amplifier circuit significantly affects the signal-to-noise ratio of Doppler signals, particularly at high frequencies, leading to a reduction in signal-to-noise ratio. Two types of operational amplifiers are selected to design the pre-amplifier circuit, and their respective output noise and signal-to-noise ratio are analyzed. Experimental validation of the simulation results demonstrates that selecting appropriate electronic component parameters can mitigate the effect of the noise gain peak on the signal-to-noise ratio of Doppler signals. This provides theoretical support for optimizing the pre-amplification circuit design of laser Doppler velocimeters, enhancing their suitability for high-speed carrier velocity measurements.