Abstract: The experiments of dissipation of pore pressure and different water content were taken to study the failure mechanism of loess basement under large area bearing in open pit dump. The results show that the shear strength of loess decreases with the increase of water content, and the change of water content and cohesion is a logarithmic linear relationship; the shearing stress decreases obviously with the increase of shearing rate. Moreover, the dissipation of loess pore pressure decreases with the increase of confining pressure; the dissipation coefficient increases with the increase of water content and its brittle failure is in low confining pressure. The results have been effectively applied in dump of Antaibao and Heidaigou coal mines for slope control, which has produced good economic and social benefits.