The　condensation　characteristic　of　R1234ze(E)　inside　an　inclined　circular　tube　(D　=　4.57　mm)　were　numerically　investigated.　The　mass　flux　covered　from　300　to　800　kg.m(-2)S(-1)　and　the　inclination　angle　varied　from　-90　degrees　to　90　degrees.　The　inclination　effects　on　film　distribution,　local　film　thickness,　local　heat　transfer　coefficient　and　velocity　profile　were　detailed　presented.　Inclining　the　tube　has　a　negligible　effect　on　heat　transfer　coefficients　at　high　mass　fluxes　and　vapor　qualities,　but　may　cause　an　increase　or　decrease　in　heat　performance　when　decreasing　the　mass　flux　and　vapor　quality.　At　the　same　inclination　angle,　slightly　higher　heat　transfer　coefficients　were　observed　for　the　down-flow　configuration.　Increasing　the　inclination　angle　would　thicken　the　film　thickness　of　thin　film　region　while　reducing　the　film　thickness　of　stratification　region,　which　affected　local　heat　transfer　performance.　Compared　with　heat　transfer　coefficients,　the　pressure　gradients　were　more　sensitive　to　the　inclination　angle.　The　local　pressure　gradients　generally　increased　with　the　inclination　angle　for　down-flow　configuration.　While　the　reverse　was　true　for　up-flow　configuration.　The　simulated　heat　transfer　coefficients　and　pressure　gradients　were　compared　with　predictions　of　well-known　correlations.　The　pressure　drop　models　developed　for　horizontal　tubes　were　not　able　to　precisely　predict　the　data　of　inclined　tubes.