Phosphorus　is　considered　as　a　promising　anode　for　Na-ion　battery　because　of　its　high　theoretical　capacity　of　2595　mAh　g(-1).　In　this　study,　two　phosphorus-carbon　(P-C)　composites　with　well-controlled　compositions　and　nanostructures　of　P　and　C　have　been　developed:　P@YP　composite　with　P　confined　within　porous　structure　of　YP-80F　carbon　and　P@CNT　with　unconfined　P　deposited　on　the　surface　of　carbon　nanotube.　The　structure　and　electrochemical　performance　of　these　two　composites　have　been　studied　to　illustrate　the　effect　of　nanostructures　of　both　C　and　P.　P@YP　composite　with　appropriate　amount　of　P　confined　in　nanopores　can　accommodate　its　large　volume　change　upon　sodiation/desodiation　and　enable　a　stable　solid-electrolyte　interphase　(SEI),　ensuring　an　excellent　long-term　cycling　stability　with　superior　capacity　retention　of　92%　after　100　cycles　and　46%　after　1000　cycles.　In　contrast,　the　P@CNT　composite　with　unconfined　P　nanostructures　shows　a　rapid　capacity　decay　with　capacity　retention　of　similar　to　40.6%　after　100　cycles,　most　likely　due　to　unstable　SEI　during　cycling,　caused　by　the　large　volume　changes　of　unconfined　P　in　the　P@CNT　composite.　The　well-designed　nanostructured　P-C　composite　with　P　confined　within　porous　structure　of　carbon　is　demonstrated　to　greatly　enhance　the　electrochemical　performance,　leading　to　promising　long-term　cycling　stability.