Jinqi Bridge on the Wudang-Changshun Expressway in Guizhou Province crosses the Maotiao River，and the poor geological conditions such as dangerous rock mass and collapse accumulation body on the bank slope of the river are relatively developed，which seriously affects the site selection and safety of the bridge.In order to study the stability of the high and steep bank slope of the bridge，the paper explored the main poor geological conditions in the bridge site through a comprehensive air-ground investigation.By means of numerical analysis，InSAR，and other technologies，the movement range of dangerous rock mass on the bank slope was quantitatively evaluated.The stability and deformation mode of the accumulation body on the bank slope under the action of internal and external dynamics were elucidated.The results show that：① The poor geological conditions in the bridge site are mainly cliff unloading zone，dangerous rock mass，and collapse accumulation body，and the failure mode of dangerous rock mass is pulling-toppling；② The movement distance of W 1，W2，and W 3 dangerous rock mass after failure is about 65 m，57 m，and 320 m，respectively，which affects the Wudangan abutment and Changshun pier；③ The accumulation body on the Wudang bank slope is very stable under normal，rainfall，and rainfall + earthquake conditions.The accumulation body on the Changshun bank slope is stable under normal and rainfall conditions.Under the rainfall + earthquake conditions，the shear plastic zone at the contact surface between the upper accumulation body and the bedrock is completely connected，and the accumulation body is in an unstable state.The failure mode is creep-pulling.The research results can provide a reference for comprehensive investigation and stability analysis of high and steep bank slopes of bridges in deep canyons and steep cliffs in Guizhou Province.