With the steady progress of transportation infrastructure construction in China,a large number of bridges with high piers have been built in the mountainous southwest region,a part of the Alpine-Himalayan seismic belt where earthquakes are frequent.Thus,research on structural seismic response has always attracted close attention.In this paper,we study the dynamic instability mechanism,seismic response,and performance of super-high bridge piers,develop reasonable structural strategies,and suggest design proposals to avoid dynamic instability.Assuming a plane section and considering the geometric non-linear effect induced by large displacement deformation of super-high piers,a numerical model of super-high piers is established.The governing differential equations of super-high piers are established,and a displacement shape function is proposed according to the force-deformation constitutive law of members.The Runge-Kutta method is used to solve the equation.Based on the B-R kinematic criterion,the dynamic instability mechanisms of super-high piers are discussed.The results from the numerical model under the dynamic conditions of various seismic waves are discussed,and longitudinal and lateral displacement at the top of high piers is studied.Theoretical analysis and calculation results show that the dynamic instability of super-high piers is closely related to pier geometry,mass distribution,and boundary conditions.The dynamic instability time of piers decreases with an increase in the peak acceleration of seismic waves.The relationship between the acceleration load and instability time shows strict correlation.The results from the example show that the method in this paper is simple,feasible,and correct.Using the theory in this paper,the dynamic instability time and acceleration load critical value of super-high piers can be calculated accurately.The theory is therefore significant in theoretical analysis and engineering practice regarding the dynamic instability of super-high piers.