The　heat　transfer　and　resistance　characteristics　of　spiral　wall　with　internal　rib　in　supercritical　(ultra-supercritical)　boiler　at　different　inclination　angles　are　explored,　and　experiment　is　carried　out　in　a　Φ　35　mm×7.75　mm　six-head　internally　ribbed　tube.　Experimental　parameters　are　as　follows:　pressure　from　22.5　to　28　MPa,　heat　flux　from　300　to　500　kW/m2,　mass　flux　from　600　to　1　000　kg/(m2•s),　inclination　angles　of　the　internally　ribbed　tube　from　5°　to　45°.　The　effects　of　inclination　angles　and　mass　flux　on　the　heat　transfer　and　resistance　characteristics　of　the　supercritical　water　are　discussed　according　to　the　experimental　results,　five　heat　transfer　correlations　are　used　to　evaluate　the　test　data,　and　a　convective　heat　transfer　correlation　and　a　friction　resistance　coefficient　correlation　are　developed.　Results　show　that　the　inner　wall　temperature　and　the　heat　transfer　coefficient　are　almost　unchanged　with　the　change　of　the　inclination　angles.　With　the　increase　of　the　mass　flux,　the　inner　wall　temperature　decreases　and　the　heat　transfer　coefficient　increases.　With　the　increase　of　the　inclination　angles,　the　water　friction　resistance　coefficient　and　the　friction　resistance　pressure　drop　increase　significantly.　And　with　the　increase　of　the　mass　flux,　the　friction　resistance　coefficient　decreases　and　the　friction　resistance　pressure　drop　varies　under　different　pressures.　The　developed　heat　transfer　correlation　is　in　good　agreement　with　the　experimental　data,　and　about　95.8%　of　the　calculated　values　are　within　the　error　of　±20%　from　the　experimental　values.　The　developed　friction　resistance　coefficient　correlation　is　in　good　agreement　with　the　experimental　data,　about　84.2%　of　the　calculated　points　before　the　pseudo-critical　point　and　88.2%　of　the　calculated　points　after　the　pseudo-critical　point　of　have　deviations　within　±20%　from　the　experimental　data.　©　2020,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.