This article delves into the basic calculation and design issues of concrete bridges, including the indicator stress of bridge structures, the analysis methods of concrete box beams and steel-concrete composite beams, the cracking deflection problem of large-span prestressed concrete beam bridges, the external prestressing reinforcement method, and the active use of external prestressing steel tendons to improve the crack resistance of box beam structures. It points out the shortcomings and deficiencies of current structural analysis and reinforcement methods, I hope to have a more complete and in-depth understanding of the spatial stress characteristics and the essence of reinforcement methods of bridge structures, in order to provide useful suggestions for the design of bridge structures in China to be more refined and complete, and to promote the engineering safety and durability of bridge structures