Realizing　the　controllable　adjustment　on　textural　and　acid　properties　of　silicoaluminophosphates　(SAPOs)　is　crucial　for　obtaining　excellent-performance　catalyst　via　acid-etching　method.　However,　there　are　difficulties　due　to　the　lack　of　understanding　of　the　mechanism　of　selective　desilication　for　acid　etching.　In　this　paper,　parent　SAPO-34　were　exposed　to　a　series　citric　acid　solutions　aimed　to　investigate　the　influence　of　acid　concentration　on　the　physicochemical　properties　of　the　resulted　SAPO-34　and　elucidate　the　mechanism　of　selective　desilication.　The　results　showed　that　citric　acid　concentration　plays　a　decisive　role　in　efficiently　manufacturing　hierarchical　pore　structure　and　selectively　extracting　specific　Si　species.　The　diverse　acid　resistance　of　Si-O-Si　and　Si-O-Al　bonds　near　or　in　different　Si　species　(Si　islands　and　isolated　Si(4Al))　is　responsible　for　the　selective　desilication　of　citric　acid.　The　coupling　effects　of　the　differential　distribution　of　Si　species　in　parent　SAPO-34　and　the　selective　desilication　influence　the　generation　of　the　secondary　pore　and　the　strength　and　amount　of　acid　sites　of　the　resulted　SAPO-34.　Compared　to　the　parent　SAPO-34,　the　acid-treated　SAPO-34　exhibited　a　longer　lifetime　and　a　higher　selectivity　for　light　olefins　(ethylene　and　propylene)　when　used　in　methanol-to-olefins　(MTO)　reaction.