It is an important research field of bridge engineering to evaluate the safty and adaptability of existing bridges during the remaining service period and put forward maintenane strategies and reinforcement methods, that to put forward maintenance strategies and reinforcement methods, by using modern testing methods, testing technology, evaluation theory, structural theory, numerical simulation, mathematical statistical prediction and other theoretical methods and technical means comprehensively. Based on the literature of 2019, this paper introduces and summarizes the reliability evaluation method of existing bridges based on time-varying theory, reliability calculation method combined with engineering application, maintenance and reinforcement strategy, seismic performance and seismic reinforcement of reinforced concrete pier columns, new materials, new methods and new equipment of bridge reinforcement, etc., in addition, the research prospect is put forward from the aspects of the understanding of the existing structure performance decay, the development of new theories and methods, and the expansion of new research fields according to the actual needs.