To address the limitations of existing active electrostatic velocity measurement methods—such as significant signal attenuation along the path, high sensitivity of measurement accuracy to sensor positioning, and high complexity of selecting cross-correlation parameters—a gas velocity measurement method based on an electrostatic sensor array and active ionization is proposed. An electrostatic sensor array composed of an upstream excitation module and downstream multi-channel detection electrodes was designed. Alternating high-voltage excitation was employed to actively generate ion tracer signals with fixed frequency characteristics within the flow field. Through experiments conducted on a wind tunnel platform, the frequency characteristics, spatial attenuation, and spatial distribution of the electrostatic signals from the sensor array under alternating high-voltage excitation were systematically analyzed. Furthermore, a criterion for effective velocity screening based on the signal-to-noise ratio (SNR) and electrostatic attenuation rate was proposed. Experimental results indicate that the error of active electrostatic crosscorrelation velocity measurement is significantly influenced by signal attenuation characteristics, and the optimal measurement position varies notably with flow velocity. When the electrode pair′s SNR exceeds 5.6 dB and the signal attenuation rate is less than 1.5, both the relative error and relative standard deviation of velocity measurements can be controlled within 2% over the flow velocity range of 10~40 m/s. Additionally, the frequency of the electrostatic signal is dominated by the alternating high-voltage excitation source and remains insensitive to flow velocity. Accordingly, the cross-correlation integration time can be determined by the number of signal periods, which significantly simplifies the parameter selection process. When the integration time is set to five signal periods, the relative standard deviation of the velocity measurement results is approximately 1%.