Abstract: The lateral retaining effect of deep cement mixing piles has gradually gained attention in the application of retaining structures, such as foundation pits and wharves in soft soil areas. This study employs geotechnical centrifugal model tests to investigate the impact of deep cement mixing piles reinforcement in active zone on the lateral response of anchored sheet pile walls.Simultaneously, a three-dimensional finite element numerical analyse is conducted to inversely analysis the centrifuge test results, and to further investigate the lateral load reduction effect of the deep cement mixing pile composite foundation and the interaction mechanism between the structure and soil. The impact of foundation reinforcement parameters such as pile length, pile spacing, and pile strength on the lateral load reduction efficiency of the anchored sheet pile wall is clarified. The results indicate that the installation of deep cement mixing pile in active zone produces horizontal soil arch effect, so that the lateral loads are borne more by the piles and less by the soil between the piles, thus weakening the lateral earth pressure acting on the front wall and effectively improving the lateral displacement and the bending moment of the wall. Compared with the unreinforced foundation, the deep cement mixing pile composite foundation in active zone reduces the lateral active earth pressure on the anchored sheet pile wall by 25.6%, the bending moment by 32.4%, and the lateral displacement by 26.7%, respectively. The lateral displacement of the anchored sheet pile wall decreases with the increase in strength and length of the deep cement mixing pile, and increases with the increase of pile spacing. The lateral load reduction effect of the deep cement mixing pile becomes more prominent with greater excavation depths. When the deep cement mixing pile is end-bearing in and the pile spacing is twice the pile diameter, this allows the deep cement mixing pile to perform better lateral load reduction. The findings of this study provide insights for controlling the deformation of retaining structure and saving the project cost, offering a valuable reference for the design and construction of similar projects in the future.