Abstract: For the research on high temperature real gas effects of hypersonic flows, numerical simulation is applied to study surface recombination effect on aerodynamic characteristics by solving the 3-D Navier-Stokes equations. The studied vehicles include two types, one is the CEV-alike configuration, and an other is the HTV2-alike configuration with high L/D. The results show that surface catalytic Had less influence on the wall pressure. The wave drag is almost the same at different catalytic conditions, while the surface friction differs from each other obviously around the high compressed area, but the difference is small in the major area and backward area. Surface recombination makes big molecule congregate to the wall, which causes larger velocity gradient. Wave drag is dominated to blunt body re-entry because there is a characteristic of base compressed flow. But to the high L/D flight, because the high compressed area is small, which contributes to the whole loads unapparent, and finally the whole drag coefficient varies with the surface recombination conditions very slightly.