The flow region around the foundation pit in a soil layer with anisotropic permeability was divided into two regular parts. Then a semi-analytical solution for the two-dimensional steady seepage was obtained using Fourier transformation technique. The solution was verified through the comparison with the results obtained from the finite element software PLAXIS. Based on the semi-analytical solution, the effects of the ratio of horizontal permeability to vertical permeability α, the distance between the retaining wall and the impervious boundary L, the water level inside of the foundation pit d2, the half width of the foundation pit b on the distribution of water head along the retaining wall were analyzed, and the variations of exit gradient with the parameters were studied. Results show that the distribution of total water head along the retaining wall is curvilinear under two-dimensional seepage. The total water head becomes larger, as α, d2 becomes larger and b becomes smaller. As L becomes larger, the total water head outside and inside of the retaining wall becomes smaller and larger, respectively. The exit gradient becomes larger with the increase of α, L and the decrease of b, d2. It is unsafe to calculate the exit gradient under the assumption of one-dimensional seepage.