Experiments of large direct shear strength characteristics of rock debris piled masses with same water content and different densities are carried out. The result shows that the evenness of heap mass moisture contents and densities are very poor. The other results show that the shear stress increases with the shear displacement, has no clear peak, and displays strain hardening characteristics obviously. The sensitivity of shear strength to compactness falls drastically with the increase of rock heap mass density in the original gradation and different dry densities.