Abstract: In direct current prospecting, the forward calculation of 3D point source is complex and the calculation quantity is large, and using the Fourier transform can converted into 2D point source, but it is more complicated than that of 2D line source. This paper is based on Matlab programming, using the first boundary condition, and gives numerical solution of two-dimensional finite element of DC method with line source, through comparing with theoretical value of homogeneous half-space, the correctness of calculation results was verified. Then the high and low resistivity geoelectric models were built, the response of single side power supply and double side power supply were compared and analyzed respectively, and the corresponding apparent resistivity profile was obtained. The results show that unilateral power supply can accurately reflect the vertical position of the abnormal body, while bilateral power supply can more accurately reflect the horizontal position and the shape of the abnormal body, providing theoretical basis for actual production.