The invention discloses an electric decoupling based simplifying method for a two-direct-current-converter-system model of a generator set. The method is mainly applicable to a network structure with two symmetrical direct current converter station systems; the two direct current converter station systems are simplified into two independent direct current systems through the equivalent simplification of the method under the condition that the electrical damping characteristics of the generator set are not changed before and after the equivalent simplification is carried out, so as to realize decoupling of the two direct current systems, and the system dimensionality is lowered; when sub-synchronous oscillation (SSO) is researched, all parts of the system need to adopt detailed electromagnetic transient modes, wherein each electromagnetic transient mode comprises an alternating current system, a power transmission line, a generator electrical part, a multi-mass block shafting model, an excitation system, a speed regulator, an electric power system stabilizer, a direct current system and the like. According to the electric decoupling based simplifying method for the two-direct-current-converter-system model of the generator set provided by the invention, the simplification for a simulation model is realized.