A novel finite difference method (FDM) solution to the 2-dimensional time-independent radiative transfer equation (RTE) is proposed for small-animal imaging applications, which is based on the real physics of 3-dimensional scattering of a photon in turbid medium. The influences of the angular discretization and the spatially meshing grids on the accuracy of FDM-RTE solution are investigated and a comparison is made between the FDM-RTE calculations to the relevant Monte-Carlo simulation ones for a validation of the proposed method. The comparison shows that, as the number of the discretized solid angles is over 80, the accuracy of the FDM-RTE calculated forward photon density is insensitive to the spatially meshing grids on the transmission and side surfaces but on the reflection surface. This study provides a viable methodology to the development of the RTE-based Diffuse Optical Tomography(DOT) technology.