The invention discloses an electromagnetic scattering property simulating method based on cylindrical surface equivalent source domain decomposition. The method comprises the following steps of: establishing a model, dividing sub-regions and dissecting; opening electromagnetic current on each sub equivalent cylindrical surface and each sub scatterer, and determining the basic function coefficient of the equivalent incident electromagnetic current on each sub equivalent cylindrical surface; converting the basic function coefficient of the equivalent incident electromagnetic current on the sub equivalent cylindrical surface of a non-rotational symmetrical body into an RWG (Vector Triangle Basis Function) coefficient; determining an incident electric field generated on the surface of the corresponding sub scatterer by the equivalent incident electromagnetic current on each sub equivalent cylindrical surface, and determining scattering current on the surface of the sub scatterer in each sub-region; determining the scattering electromagnetic current on each sub equivalent cylindrical surface, taking the scattering electromagnetic current as the incident current of any other sub-region, and updating the scattering electromagnetic current coefficient on each sub equivalent cylindrical surface until the scattering electromagnetic current coefficient is balanced; and determining the radar scattering sectional area of a far field to finish the electromagnetic scattering property simulation. The invention provides a stable and efficient electromagnetic simulating method suitable for metal targets with any shapes.