For in-situ shear test on soil in slide zone，substance constituent，water content and stress history of its samples are all random to some extent; boundary restrain，restoring degree to original consolidation state and draining condition in the course of shearing are fuzzy. All these uncertain factors cause test results become variant and then have no enough geological representation. Applying in-situ shear test parameters and the results of qualitative geology description of failure surface，water ratio measurement and grading analysis to train BP network; and then depending on BP network's ability of high fault-tolerance and strong nonlinear mapping，the shear strength parameters of soil in slide zone are estimated. This method could counteract the influence of the variance of test results to some extent.