Abstract: Roof caving and rock falling occurred during the construction of Dege tunnel on the Sichuan-Tibet high? way. The characteristics of displacement and stress of surrounding rock and support were studied by numerical simulation and site test, a thorough analysis was carried out regarding the features and mechanism of roof caving and rock falling occurred at the same tunnel, and some corresponding treatment measures were proposed. The research results show that roof caving was represented by debris flow and rock falling was represented by cracked deformation; plastic zone of crushed stone occurs at tunnel crown in the course of roof caving and dilatancy occurs due to the difference of vertical stress and horizontal stress in the course of rock falling; roof caving is caused by construction disturbance due to poor self-stability of shallow-buried crushed rock mass and rock falling is induced by dead load of rock mass and blasting construction attributed to developed fissure of deep-buried sericite quartz schist. The main corresponding measures include restriction of plastic deformation and cracking development, installation of anchoring and injection support system, implementation of forced composite support and strengthening of the support parameters.