Abstract: Based on the turbulent bulk flow theory and Moody wall friction coefficients equation, 3D non linear partial differential equations of large gap annular flow field are simplified, and zero order perturbation equations derived. The static characteristics of eccentric rotor have been investigated with numerical method. The results show that there are many differences in the static characteristics of the rotor in large gap annular flow and that in bearings and seals, and the wall friction coefficient changes circumferentially. The results also show that the wall roughness and the eccentricity ratio have considerable effects on the static characteristics in large gap annular flow.