Abstract: Combined with the reinforcement principle of soil-cement mixing method,SEM was used to analyze the microstructure of undisturbed soil and treated soil in a shipbuilding base hydraulic reclamation area.From the microscopic point of view,this paper describes and analyzes the advantages and disadvantages of using the method of cement soil mixing to reinforce the deep foundation of the site under different conditions(including the original soil,the depth,the type of curing material,etc).Some suggestions are put forward to improve the strength of cement soil mixing pile,and so as to guide the actual project.