Numerical study on turbulent mixed convection in inclined plane channels, from 15˚ to 90˚ (vertical), was carried out to examine the effect of inclination on fluid flow and heat transfer distributions. The turbulent air flows upward or downward into the duct with one wall heated from bottom. Calculation results with several kinds of k-ε type turbulence models were used to compare the experimental data with those in literatures to determine suitable model. The dependents of Nusselt number on the inclination angle of both the buoyancy-aided and buoyancy-opposed flow are discussed.