This paper introduces the design of the transformation process, structural characteristics of the transformation structure, monitoring and control of the whole process of construction, traffic test, and the compression bar stability model test for the columns on the particularly slender arches on the special highway for external transportation of the Three Gorges Project, for the two bridges with a clear span of 160m, which were constructed by the transformation method. The paper describes the experience of participating in the practice of the two bridges and puts forward suggestions.