The construction conditions of the Hangzhou Bay Bridge are complex and the project scale is huge. The approach bridge accounts for about 95% of the total length of the bridge. The superstructure of the approach bridge in the offshore and mudflat areas adopts 70m and 50m span prefabricated box girders, and the whole span is prefabricated and erected. Steel pipe Pile foundation and precast piers are mostly used for the substructure of the approach bridge. Introduce the natural environment of the bridge site, design principles for cross sea long bridges, and the concept and comparison of approach bridge schemes