Abstract:Finite-element direct iteration algorithm is used in MT 2-D forward cornputation,it has the advantages of finite element and finite difference characteristics. In the paper,authors explain the basic principle of the algorithm,and design a practical program for MT 2-D forward computation. The technique involves some essential points:·Using discrete model in programming that consists of cross symmetric triangle grid.·Solving the finite-element equation system by taking the algorithm of alter- nating direction line successive over-relaxation.·Obtaining the auxiliary field by using quadratic interpolation function. Considering the influences resulting from both dielectric constant and terrain in air under TE polarization mode.Examples have shown that the technique receives satisfactory effects in computation accuracy,storage capacity,computation speed and adaptability (model adaptability and grid adaptability).