On　the　basis　of　the　experimental　study　on　the　steam　forced　heat　transfer,　the　SSG　turbulence　model　was　adopted　to　solve　the　three-dimensional　steady　Reynolds-averaged　Navier-Stokes　equations.　The　numerical　investigation　was　performed　on　the　influence　of　Reynolds　numbers　(Re),　temperature　and　pressure　on　the　steam　flow　and　heat　transfer　process　in　a　90°　ribbed　rectangular　channel.　The　results　show　that　the　variations　of　temperature　and　pressure　significantly　affect　the　steam　forced　heat　transfer　characteristics.　The　steam　heat　transfer　coefficient　and　friction　factor　will　increase　with　an　increase　in　pressure　and　decrease　with　an　increase　in　temperature.　Generally,　the　optimum　steam　thermal　enhancement　performance　can　be　achieved　for　the　steam　flow　at　the　suitable　Re　number,　relative　low　temperature　and　medium　pressure.　The　change　in　Re　number　has　little　effect　on　the　performance　of　steam　cooling.