The invention discloses a satellite overall plan confirmation system based on a multidisciplinary optimization and a realization method. The satellite overall plan confirmation system comprises a satellite total technical index extraction module, a satellite total technical index distribution module, each subsystem technical requirement formation module of a satellite, a satellite system design subject decomposition module, a design structure matrix generation module, a satellite system design subject analysis modeling module, a satellite system optimal modeling module, a model simplification module, a two-stage collaborative optimization modeling module, a collaborative optimization solving module, a satellite total technical index database, a model number base line design database, a design parameter library, a model library and a satellite overall plan parameter output module. The multidisciplinary design optimization of the satellite overall plan is realized by system index extraction, design task subject decomposition, design subject analysis modeling, design structure matrix construction, satellite overall plan multidisciplinary design optimization description, model simplification and two-stage collaborative optimization modeling and solving.