Peat soil is difficult to consolidate and seriously endangers engineering safety because of its high organic content，high water content，high compressibility，low strength and slow consolidation.Relying on the expansion project of an overseas existing steel sheet pile wharf，this paper draws up a variety of reconstruction and expansion plans and structural plans in view of its outstanding characteristics such as deep peaty soil soft foundation，small yard area，serious structural damage of the old wharf，limited renovation space，and operation in construction stage.The advantages and disadvantages of each scheme are analyzed from the aspects of wharf operation，structural reliability，economy and construction difficulty，and finally the recommended scheme is proposed to adapt to the old wharf reconstruction and expansion project under the condition of deep peat soil soft foundation.Besides,the key technical difficulties and precautions in the construction process are analyzed，which can provide reference for similar projects.