Abstract: As an important branch of mechanics, rock mechanics is an important foundation for civil engineering, water conservancy and hydropower, and mining engineering. This paper first investigates the difficulties existing in rock mechanics teaching, and analyzes the advantages of numerical simulation technology in teaching. Then, based on the case of rock uniaxial compression failure process, the numerical simulation technology combining image acquisition and particle flow simulation is used to demonstrate the rock transient failure process, and reveal the failure mode and failure mechanism of the rock when it is subjected to an external force. It shows that numerical simulation technology has the advantages of full scale, full dimension and full time in rock mechanics teaching. The teaching effect of numerical simulation technology in describing the rock failure process is demonstrated.