Abstract: In order to effectively prevent the malicious attack of transmission system and the adverse impact caused by accidental faults, a power system voltage stability monitoring method based on stealth strategy is proposed. The Thevenin equivalent parameters of the system were calculated by using the multi-port equivalent circuit of the power system, and a variance suppression algorithm index was proposed to ensure the rapid and accurate detection of attacks, false data injection and equipment faults. A potential stealth framework was further designed, so that the particle swarm optimization could accurately reconstruct the system load measurement, and estimate the attack vector according to the number of damaged phasor measurement units, so that the load loss could be avoided through appropriate operation decisions. The effectiveness of the proposed method is verified by multiple attack scenarios of three cases.