Abstract: Two 1g model tests in the laboratory are carried out to investigate the influences of the spudcan penetration and extraction on the adjacent piles in the sand and clay. The variations of the spudcan penetration and extraction resistance, the soil displacement and the pile shaft bending moment distributions during the spudcan penetration and extraction are analyzed in this study. It is found that the penetration resistance of the spudcan in the clay initially increases with the increase of the spudcan penetration depth and then gradually keeps stable after reaching a certain limit value, while in the sand it keeps linear increasing with the penetration depth. The extraction resistance in the clay keeps constant until the spudcan is lifted near the soil surface, where it drops to zero. In the sand, the spudcan extraction resistance rapidly increases at the initial stage, and then decreases rapidly. After reaching the maximum value, it begins to uniformly decrease at a certain rate. A comparison between the calculated and the measured values of the spudcan resistance indicates that the soil strength is weakened by the spudcan penetration into the soil mass. It is found from soil mass displacement measuring system that the spudcan in the clay has a greater influence in the vertical direction and has a greater influence in the horizontal direction in the sand. And there are different degrees of the back-siltation at both sand and clay sites, and at the sand site the back-siltation is more obvious. Different soil movement distributions lead to different responses of the adjacent pile: in the clay, the positive bending moment in the upper part of the pile shaft is larger, and the negative bending moment of the lower part of the pile shaft is smaller. And the positive bending moment in the upper part of the pile shaft in the sand is smaller and the negative bending moment in the lower part of the pile shaft is larger. In the process of pile penetration, the maximum bending moment along the pile shaft gradually increases with the spudcan penetration and its position moves downwards at the same time. When the spudcan penetrates to a certain depth, the maximum bending moment remains basically unchanged. However, the adjacent pile only displays a slight decrease in its bending moment during the spudcan extraction. The research results given by this paper can provide a reference for the calculating vertical bearing capacity and ultimate uplift force of the spudcan of the drilling ship platform, and a reference for evaluating the pile shaft response in different soil masses.