In　order　to　create　the　system-level　model　of　complex　embedded　system　effectively,　POOSL-based　system-level　modeling　methods　were　put　forward,　including　hierarchical　modeling,　object-oriented　modeling　techniques　and　resource　modeling　method　based　on　Y-Chart.　The　correctness　and　effectiveness　of　system-level　modeling　methods　were　demonstrated　by　the　modeling　and　performance　analysis　of　wireless　access　system.　The　abstract　model　of　the　wireless　access　system　was　built　by　using　POOSL.　Through　the　simulation　of　the　model,　the　influence　of　the　parameters　such　as　minimum　contention　window　(CWmin)　and　number　of　active　stations　on　the　performance　metrics　was　given.　Simulation　results　show　that　the　proposed　system-level　modeling　methods　can　be　used　effectively　in　the　modeling　for　complex　embedded　systems.