The prediction of landslide imminent sliding time can be established according to the time curve of landslide deformation. But the existing prediction models of landslide imminent sliding time have not unified the calculation interval. So the time prediction value obtained by the same model in different calculation intervals may be quite different. Taking Longjingcun Landslide in Guizhou Province as an example, this paper analyzes the fine deformation data of the landslide with the Saito time prediction model. The calculation range of the deformation for the prediction of the time of imminent sliding is determined to be between 70 and 75 degrees of tangent angle. According to the deformation curve, the landslide has obvious upward warping characteristics when it is imminent sliding, which leads to the occurrence time of the landslide ahead of time. By analyzing the ratio between the tangential gradient and the segment gradient of the curve, a correction coefficient of 0.5 is introduced to correct the time prediction value of landslide. The results show that the improved prediction method of landslide deformation imminent sliding time has good accuracy and applicability.