To better understand the effects of rotation on the internal channel heat transfer characteristics, the flow and heat transfer condition in an internal channel with 90° ribs are investigated using three-dimensional numerical simulation method. The inlet Reynolds number is 17,000 and three outlets mass flow discharge ratio is 1:2:1. The Rotating number and the hydraulic diameter divided by radius of gyration range from 0 to 0.09 and 0 to 69.6, respectively. The influence of Rotation number and Radius of gyration on heat transfer coefficient were achieved. Results show that the pressure coefficient increases along radial outflow and decreases along radial inflow due to rotational force; in the trailing surface, Nusselt number (Nu) in radial outflow passages increases and the Nu in radial inflow passage decreases with the augment of the rotation number, the variation of Nu in the leading surface contrary to that of the trailing surface; the Nu along the flow direction in trailing and leading surface are slightly enhanced when gyration radius to hydraulic diameter ratio increase, the surface heat transfer coefficient is affected on the variable radius of gyration.