An experimental study is performed to investigate the high pressure steam condensation heat transfer in a large diameter condenser tube which is adapted for passive systems in Advanced Nuclear Power Plants. Experiments are conducted with high pressure steam in a single vertical tube with an inner diameter of 46 mm at a maximum pressure of 7.5 MPa, The film condensation heat transfer coefficients in the vertical tube are calculated by the difference of measured tube wall temperatures, and the two-phase pressure drops in the condenser tube are also measured. A new turbulent annular film condensation model is developed on the basis of the similarity of pipe flow and annular film flow. The present model gives better results than those of the Shah model in comparison with the experimental data.