This　work　studied　Precise　Point　Positioning　(PPP)　by　using　multi-system　GNSS　data　with　different-system　combined　forms　according　to　the　coordinates　of　the　International　GNSS　Service　(IGS)　weekly　solution.　The　work　was　also　proceeded　based　on　the　data　from　the　precise　ephemeris　and　clocks　of　GBM　products　released　by　the　Geo　Forschungs　Zentrum　Potsdam　(GFZ)　and　8　IGS　observation　stations　in　the　Asia-Pacific　region.　The　optimal　combination　mode　of　multi-system　combined　PPP　solution　is　obtained　by　taking　the　coordinates　of　the　station　in　the　IGS　weekly　solution　as　a　reference.　Simulation　of　dynamic　multi　system　combination　PPP　shows　that　GPS　positioning　performed　best　in　the　single　system,　whereas　dual　system　combination　significantly　improves　the　positioning　performance　compared　with　that　of　the　single　system.　The　GPS/GLONASS　combination　exhibits　better　positioning　performance,　while　multi-system　combination　further　increases　the　positioning　accuracy.　In　particular,　the　accuracy　in　horizontal　and　vertical　directions　of　GPS/GLONASS/BDS/Galileo　is　better　than　2　and　3.　5　cm,　respectively.　Quantitative　evaluation　on　the　PPP　solution　results　using　the　Post　Processed　Kinematic　(PPK)　results　as　a　reference　indicates　that　the　GPS/GLONASS/BDS/Galileo　combination　has　the　best　positioning　performance.　Comparisons　from　the　static　simulation　dynamic　results　suggest　that　the　positioning　performance　becomes　slightly　worse　when　the　root　mean　square　error　(RMSE)　of　NEU　in　the　three　directions　are　2.　24,　5.　27,　5.　8　centimeters,　and　the　convergence　time　are　17.　08,　22.　35,　54.　08　minutes,　respectively.　©　2022,　The　Editorial　Board　of　Journal　of　Basic　Science　and　Engineering.　All　right　reserved.