In order to make the 3D CD equation to maintain auto up-wind and skew up-wind under high Reynolds number, on the basis of 2D scheme, this paper focuses on development of difference scheme of 3D non-liner convection item. Exponent function is used as the weighted coefficient of auto up-wind, and the irrational case some grid point gained absolute advantage is not formed. When the velocities of every direction are not equal, the primary flow velocity and weighted coefficients are received. Weighted coefficients of 27 points’ scheme are obtained from center points of face to middle ones of edge to corner ones via geometrical transformation of space. It takes into account the effect of corner points, so it kept auto up wind. It is compared with FA method and results show the scheme can’t change to simple up-wind by the increasing of Reynolds number. It can be applied to the solution of fluid-flow, temperature and concentration problems.
