[Objective] To analyze the dynamic response of concrete filled steel tubular pile structure under the impact of the load of debris flow in order to provide scientific support for the design of the structure.[Methods] The numerical simulation of concrete filled steel tubular pile structure was carried out for three different load conditions using finite element analysis software ANSYS

and the stress

strain and displacement response of structure was analyzed to detect the most unfavorable load conditions.[Results] The impact of large rock at the top of the pile pipe of empty reservoir was the most unfavorable load condition. Among three kinds of load conditions

the impact force was the main factor causing structural damage. The concrete filled steel tubular pile had good anti-impact performance. Under the smaller plastic deformation

the structure bear a large impact force. The larger the component stiffness

the greater the peak impact force peak. The connecting part of the pile pipe and the beam pipe

the root of the pile pipes and restrained beam pipes were the weak parts of the dam

so the strengthening measures should be taken into the design.[Conclusion] Concrete filled steel tubular piles is a material saving blocking structure

and it has good stability and anti-impact performance.