Abstract: To enhance the rationality of design schemes for asymmetric continuous steel box-girder bridges in mountainous terrain, we took an asymmetric continuous rigid frame bridge with high-piers and large-spans of reconstruction project of Baihetan Hydropower Station as the research object, and introduced the overall design and upper and lower part design of the bridge. Using the finite element software of Bridge Doctor and Midas Civil, detailed calculations were conducted on the static calculation analysis, high-pier stability analysis, and seismic analysis of the bridge. The calculation results indicated that the design scheme of this bridge was reasonable, the stress on the main beam met the requirements of the ultimate bearing capacity state and the normal service limit state. The stability coefficient of the structure during the construction and bridge operation phases was greater than four. The calculated bending moment of the bridge pier under the E2 seismic leveling action was less than its initial yield bending moment, and it was in an elastic working state, meeting the established seismic performance goals. The research results can provide references for the design of similar bridges.