Abstract: In this paper the problem of the foundation bearing capacity of semi-infinite plane strain soil body is analyzed with the use of stress-dropping strain-softening model,which is used to simulate the stress-strain-softening relation of soil.The computation of the bearing capacity is finished with the mixed use of characteristic curves method and boundary elements method.It is shown that both the model and algorithm is reasonable and correct by comparing the results with Prandtl's solution and other computational results.