This paper aims to address the issue of low-frequency band noise in the reference source of the spatial inertial sensor AC actuator drive circuit, which can negatively impact its control accuracy. A noise suppression method involving parallel connection of voltage references is adopted. The power spectral density of the low-frequency band noise of the voltage reference is theoretically calculated and the theoretical noise is deduced. Various reference sources with different reference quantities were developed based on the principle of parallel noise reduction. High-precision test instruments were used to detect the output voltage of the reference source online under shielding conditions. The actual voltage noise spectral density was obtained after signal analysis and processing. The test results indicate that using a parallel reference source reduces the output voltage noise spectral density to 2.25 μV/Hz1/2 at 1millihertz. This scheme significantly reduces electronic noise in the millihertz frequency band compared to using a single reference, which had an output voltage noise spectral density of 19.90μV/Hz1/2. Paralleling \(n\) identical voltage references can reduce the noise to approximately \(1/\sqrt n\) of the noise of a single reference, which is consistent with the theoretically calculated noise. This establishes a high-precision voltage reference for the actuator circuit of the spatial inertial sensor.