Abstract：Based on various examples for the long-term strength of landslide soil，influential factors of the long-term strength of landslide soil，such as water content，granulometric composition，mineral density，testing condition，composition of mineral，chemical composition of landslide soil，and water quality，are considered to analyze the attenuation characteristics of mechanical parameters of structural plane. The results show that it is possible to evaluate the attenuation characteristics of landslide soil with semi-quantification method，and the parameter values are not less than low values of saturation testing usually. It is feasible to use the dynamic and static evaluation method of slope stability to offer new dynamic and static methods to evaluate the mechanics parameter of landslide soil in the engineering working life. Through the application in the creep mass—B section of Longtan hydropower station，the reliability is proved to be successful.
