In order to enhance the seismic stability of sand and gravel in the dam body of the Karabelli Water Conservancy Hub Project in Xinjiang, the prototype model test area was established based on the construction parameters of the original dam. The cemented sand and gravel were formed by cement grouting, and indoor shear characteristics of cement cemented sand and gravel were studied. The results show that the sand and gravel material form a “dense-skeleton” structure after rolling. By cement grouting, the shear parameters such as internal friction angle and cohesion are greatly improved. The strength of cement, the bond strength between cement and gravel, and the normal stress play a major role in the shear strength of cemented sand and gravel. Under shear stress, the internal micro cracks gradually develop into penetrating cracks, causing the failure of cement cemented sand and gravel. Due to the interlocking effect and shear dilatancy effect between particles, the residual cohesion of cement grouting cemented sand gravel does not significantly decrease.