The invention discloses a generalized forced oscillation-based voltage fluctuation analysis method and system. The existing research on generalized forced oscillation mainly focuses on the power angleoscillation problem of a power system, and relatively little attention is caused to the same important voltage oscillation problem. The technical content adopted by the invention comprises the stepsthat a time domain curve of power fluctuation and voltage fluctuation of each node in a network is obtained; according to the power flow equation of the network and the power fluctuation curve of eachnode, a time domain curve of the voltage fluctuation proportion component is obtained by point-by-point calculation; the time domain curve of the voltage fluctuation and the time domain curve of thevoltage fluctuation proportion component are subjected to difference solving, and a resonant component time domain curve is obtained; and the resonant component time domain curve is used for calculating to obtain a voltage fluctuation resonance component power spectrum and voltage oscillation mode information. According to the method, the mode information of voltage oscillation is obtained by calculating the resonant component power spectrum, so that the analysis of the voltage fluctuation under the generalized forced oscillation is realized.