Based on the principle of fictitious displacement from structural mechanics, this paper made a systematic analysis for the stress and deformation of casing string with centralizers in curved boreholes. With the help of the principle of space analytic geometry, this paper developed the analytic formulas of spacing for casing centralizers in three-dimensional curved boreholes, took the influence of axial forces into account while calculating the lateral loads of the centralizers,and introduced friction forces on the centralizers into the calculations of the axial loads.Through calculating，this paper pointed out the development direction to solve casing running and cementing in horizontal well.