To　explore　the　heat　transfer　characteristics　of　rifled　tube　water　wall　in　the　supercritical　(ultra-supercritical)　boiler,　an　experiment　was　carried　out　in　a　35　mm×7.75　mm　upwards　inclined　rifled　tube　at　different　inclination　angles　from　5°　to　90°.　The　experimental　parameters　are　as　follows:　pressures　from　15　to　28　MPa,　mass　flow　rate　from　600　to　1000　kgm-2s-1,　heat　flux　from　300　to　500　kWm-2.　The　wall　temperature　characteristics　were　compared　between　the　rifled　tube　and　the　25　mm×3　mm　smooth　tube.　The　effects　of　inclination　angles,　mass　flow　rate　and　pressures　on　the　heat　transfer　characteristics　of　subcritical,　near-critical　and　supercritical　water　in　the　rifled　tube　were　discussed.　The　heat　transfer　correlations　of　supercritical　water　in　the　rifled　tube　at　different　inclination　angles　were　developed.　The　results　revealed　that　the　rifled　tube　used　in　the　experiment　had　the　property　of　delaying　heat　transfer　deterioration　and　enhancing　heat　transfer.　The　heat　transfer　characteristics　of　the　rifled　tube　at　different　inclination　angles　were　different.　The　mass　flow　rate　had　little　influence　on　the　heat　transfer　coefficients　in　the　two-phase　region　at　subcritical　pressure.　And　with　the　increase　of　mass　flow　rate,　the　heat　transfer　coefficients　increased　at　near-critical　and　supercritical　pressure.　The　heat　transfer　coefficients　at　15　MPa　were　higher　than　those　at　other　pressures.Under　supercritical　pressure,　as　the　pressure　increases,　the　heat　transfer　coefficient　of　the　large　specific　heat　zone　decreases.　©　2021,　Editorial　Board　of　CIESC　Journal.　All　right　reserved.