Optical　synthetic　aperture　(OSA)　imaging　system　is　an　effective　method　for　astronomical　telescopes　to　realize　super-resolution　imaging,　which　has　important　applications　in　astronomical　observation　and　space　remote　sensing.　The　time-division　multiplexing　sub-aperture　array　is　a　potentially　powerful　way　to　construct　the　larger　array　configuration　by　changing　the　basic　array　configuration　several　times　with　less　apertures.　In　this　paper,　according　to　the　theory　of　incoherent　optical　imaging,　the　physical　mechanism　of　space/frequency　domain　response　of　OSA　system　is　discussed.　From　the　basic　pinhole-aperture　array　to　the　circular-aperture　array,　the　evolution　of　the　point　spread　function　(PSF)　and　the　modulation　transfer　function　(MTF)　is　analyzed.　The　inherent　laws　and　imaging　differences　between　the　time-division　multiplexing　sub-aperture　array　and　the　traditional　synthetic　aperture　array　are　revealed.　Also,　it　is　shown　that　under　the　specific　array　condition,　the　reconstructed　image　obtained　by　the　time-division　multiplexing　synthetic　aperture　system　can　approach　the　imaging　quality　and　resolution　given　by　the　traditional　synthetic　aperture　array.　It　provides　a　new　perspective　for　the　array　configuration　design　of　OSA　imaging　system.　©　2022　SPIE.