The design and production of the in-tube concrete is the key technology for building CFST arch bridges. The grouting of CFST is recognized as one of the most important processes in the construction of CFST arch bridges, as it directly affects the quality and safety of the built CFST arch bridge. During the sustained development of CFST arch bridges, the debonding issue of arch ribs has constantly existed and is difficult to solve. As the span of CFST arch bridges increases, the above issue endangers structural safety seriously and restricts the development of span. In order to solve the debonding problem, this chapter introduces the construction technique of vacuum-assisted grouting, the preparation method of in-tube concrete and the associated new materials alongside technologies.