The invention discloses an electromagnetic characteristic 
analysis method and 
system for an electrically large-size target with a complex structure, and the method comprises the steps: carrying out the surface 
triangulation of the target, setting a regional 
decomposition seed, completing the regional autonomous 
decomposition of the target based on the 
decomposition seed, obtaining a plurality of decomposition parts, and 
numbering the decomposition parts; creating a plurality of parallel threads, specifying a main thread and sub-threads, and distributing the number and serial number of decomposition parts responsible for each sub-thread; for each sub-thread, constructing a comprehensive function for all responsible decomposition parts, compressing the self / 
mutual impedance matrix and the excitation matrix of the decomposition parts by utilizing the comprehensive function, and reporting a result to a main thread; the main thread detects connection boundaries between different decomposition components, and calculates a self / 
mutual impedance matrix and an excitation matrix of the connection boundaries; and constructing a target overall compression matrix equation, solving the equation,and combining with the comprehensive 
function definition to obtain the electromagnetic characteristics of the target in space. The method solves the problems of low 
processing efficiency and the likein the prior art, and greatly improves the comprehensive 
processing efficiency of the SBFM.