The invention discloses a parameter identification method for a space coupling parameter system. The method comprises the following steps that 1, a multi-input multi-output space complex system model including a coupling unit is built according to the input and output relation of the space coupling parameter system; 2, a space complex system is divided into a plurality of subsystems with coupling parameters, and the parameters, to be identified, of the linear portions and the non-linear portions of the subsystems are identical; 3, each subsystem is divided into a linear subsystem and a non-linear subsystem, the system parameters of the linear subsystem and the non-linear subsystem of the same subsystem are identified through two-stage hierarchical identification, and the identification results of the corresponding subsystems are obtained; 4, according to the dividing sequence of the subsystems of the space complex system, the identification result of each subsystem is transmitted to the next subsystem, and replaces the identification result of the last subsystem at the last moment; 5, the step 3 and the step 4 are repeated until the identification requirement is met to output the identification result.