Abstract: Through the elastic center method simplify the catenary system of fixed-end arch force method equation,using curvilinear integral approximate curve fitting to simplify the arch axis,vault redundant force influence line fixed-end arch structure is derived analytical expression,moving load is studied and the measuring point,damage,the relative position between the rule,get any point before and after the structural damage analytic expressions of deflection influence line,then the analytical solution of curvature difference of deflection influence line before and after structural damage is solved.The research shows that when the moving load is applied to the damage area of the arch structure,the deflection influence line difference curvature curve has a sudden change.It is theoretically proved that this index can be used to identify the damage of the fixed-end arch structure,and then the deflection influence line difference curvature damage identification index is proposed.The arch rib of the main stressed component of fixed-end arch bridge was taken as the research object.The damage degree-amplitude relationship formula was fitted by constructing the difference curvature amplitude curve of deflection influence line under different damage conditions,and the damage degree was inverted to achieve the accurate quantification of the damage degree,which was verified by the calculation example of a deck box arch bridge structure model.The results show that the proposed damage identification method is effective for arch bridge structure damage identification and has engineering application value.