This article focuses on the complex geological characteristics encountered in the reinforcement of the complex interlayer foundation between land and sea in a port project in Bangladesh，which makes it difficult to predict the reinforcement effect，as well as the problem of seismic liquefaction in the soft clay and fine sand interlayer soil site.Based on the geological conditions of the project site，functional requirements for site use，engineering characteristics and other conditions，the reinforcement effect of the combination of plate pre compression and precipitation dynamic compaction under the site conditions is studied.Based on the experimental block of the project，by comparing and analyzing the physical and mechanical indicators of the soil before and after reinforcement，and studying the settlement time history curve，pore water pressure time history dissipation curve，etc.，the process characteristics of inserting plate preloading combined with precipitation dynamic compaction reinforcement and the reinforcement effect on the original soil and hydraulic fill soil are obtained.The results show that the combination of plate precompression and precipitation dynamic compaction method has good adaptability for complex interlayer soil filling sand sites，and the reinforcement effect can meet the design bearing capacity and post construction settlement control requirements.This method has a certain effect on reducing the liquefaction of sand layers.The research results have certain guiding significance for guiding the design of complex interlayer soil reclamation sites in South Asia