Abstract: The medium-high frequency oscillation problems caused by multiple power electronics in the "double high" system are becoming more and more significant. Traditional oscillation detection methods have difficulty in balancing the accuracy and sensitivity of medium-high- frequency oscillation detection, and are no longer able to meet the new demands of oscillation detection in the medium-high frequency range. For this reason, a fast detection method for medium-high frequency oscillation based on equal-band multi-channel signal tracking and screening is proposed in this paper, including fundamental frequency notch link, equal-band multi-signal tracking and screening channel and threshold judgment link. First, the power frequency notch link is used to eliminate the fundamental frequency signal in the signal to be detected, and then enters the equal-band multi-signal tracking and screening channel. Each channel realizes the fast tracking of the oscillation signal in a specific frequency range through a phase-locked loop (PLL) and low-pass filters. Multi-channels work together to cover the medium-high frequency range. Lastly, the output of each channel is transferred to the threshold judgment link, and the fast detection of the rapid detection of the medium-high frequency oscillation signals is realized. The parameters design principle and method of the power frequency notch link, the equal frequency multi-signal tracking and screening channel and the threshold judgment link in the fast detection method of equal-band multi-channel signal tracking and screening are proposed. The effectiveness of the proposed method is verified in the cases of the medium- frequency and the high-frequency numerical signals, the high-frequency oscillation of MMC system and the medium-frequency oscillation of MMC system. The results show that the proposed detection method can quickly track the frequency and amplitude of the medium-frequency oscillations, and the detection error of oscillation frequency can be actively controlled by setting the number of channels. It has good accuracy and sensitivity for the detection of medium-frequency oscillations and meets the detection needs before early warning and suppression of medium-frequency oscillations.