The present invention discloses an convergence RLC circuit model-based method for analyzing subsynchronous resonance in a power system. The method comprises the following steps of: establishing a power plant model and a series compensated transmission line system model so as to acquire a non-linear differential equation model of each subsystem; generating a state equation model according to a parameter under a particular working condition and the non-linear differential equation model; generating an algebraic equation model according to the Laplace transform and the state equation model; acquiring a final equivalent resistance model so as to acquire a series resonance point; aggregating the final equivalent resistance model into an equivalent second order RLC electric circuit model according to the series resonance point; and quantifying SSR analysis. According to the analysis method provided by an embodiment of the present invention, the final equivalent resistance model is aggregated into the equivalent second order RLC electric circuit model, so that the SSR analysis is quantified, thus implementing the accurate quantification evaluation of SSR, reducing analysis errors and improving analysis accuracy.