Bridge foundation slope is a complex structural system composed of pile foundation and slope, in which its deformation and stability requirements, reinforcement measures and key reinforcing positions are significantly different from natural slope. In combination with the foundation slope of some bridge in southwest, some problems, including the failure mode of slope under bridge load, the restriction effect of prestressed anchor bars on horizontal displacement, the feasibility of making foundation piles as anti slide piles to save reinforcement workload, and key reinforcing positions ,are all profoundly analysed by numerical simulation and limiting equilibrium analysis. In the end, the reinforcement measure is presented.