Abstract: Three-dimensional coronal structure of Carrington rotation 1935 at May 1998 is obtained by using a three-dimensional numerical model of ideal magnetohydro dynamic equations. In this numerical model, MacCormark-Ⅱ scheme is employed for the discretization of the governing equations in computational domain and non- reflecting projected-characteristic condition is adopted at inner boundary to keep the simulation stable and the solution self-consistent. With the numerical model, iteration is carried out with initial magnetic field constructed from photosphere observation at 1935 Carrington rotation by Legendre series expansion and finally approaches a steady state. The iteration results show that:(1) magnetic field on source surface is nearly in radial direction with non-radial magnetic field component no more than 2μT near the neutral line. (2) The value of radial magnetic field component on source surface has no much variation except near the neutral line. This agrees with Ulysess observation. (3) The magnitude of radial magnetic field component at 1 AU, calculated from that on source surface by rule of r^-2, approxi mates observation better than that obtained by potential model. (4) 3-D numerical coronal structure agrees qualitatively with observation. The 3-D numerical results also show that magnetic field dominates global solar wind structure, in which density of solar wind is high and speed is low in close magnetic field and near current sheet, while density is low and speed is high at open magnetic field.