The invention belongs to the technical field of wind power plant analysis and calculation, and particularly relates to an equivalent calculation method for a large-scale wind power plant of a parallelstructure. The method comprises the steps: establishing a wind power plant linearized state space model for the wind power plant of the parallel structure formed by M wind power generators; performing equivalent transformation on the state variables of the wind power plant, and similarly transforming a linearized state space matrix of the wind power plant into a block diagonal matrix; decouplingthe linearized state space model of the wind power plant in a manner: M-1 subsystems is formed by connecting a wind driven generator to an infinite bus via a line, and the M-th subsystem is formed byconnecting a wind driven generator into an external power system through a correction network; according to the linearization model of the M-th subsystem, reversely deducing a nonlinear model of the M-th subsystem to obtain a single-machine equivalent model of the wind power plant; dividing the M-th subsystem into two interconnection systems, namely a wind power plant part and an external power part, and solving the interface state variables of the interconnection systems and the dynamic process of the wind power plant.