Optical　sparse-aperture　system　can　be　designed　to　obtain　high　resolution　in　astronomical　object　imaging　with　several　independent　small-aperture　telescopes.　However,　the　images　from　separated　telescopes　are　not　only　overlapped　but　also　have　same　phase.　Ordinarily,　the　phase　of　each　sub-aperture　can　be　obtained　by　wave-front　sensing　technology,　such　as　phase　retrieval　algorithms,　but　this　method　requires　more　than　one　CCD　and　interfere　the　wave　front.　In　this　work,　we　use　the　differences　between　PSFs　from　each　sub-array　to　get　the　type　and　size　of　the　co-phase　error.　Finally,　submit　the　results　to　mechanical　system　as　a　feedback　for　phase　retrieval.　We　used　Golay-3　system　as　an　example　to　verify　the　above　conclusions.　The　output　is　consistent　with　the　pre-set　value　within　the　allowable　error.　The　results　show　that　this　method　is　feasible　and　reasonable.　©　2009　SPIE.