The three-dimensional nonlinear finite element numerical model of super-long pile and soil is established.The loading characteristics of super-long pile after preloading of soft soil foundation are studied by preloading drainage consolidation method,and the changes of soil consolidation settlement,side friction resistance of pile body,pile top displacement load curve and axial force of pile body are analyzed.The preloading time,preloading load and preloading effect of different soil are analyzed by the control variable method,the sensitivity of the single pile and the group pile to the preloading are compared and the influence of consolidation degree on the bearing behavior of super-long piles is analyzed.The results show that preloading can improve the foundation and the bearing capacity of super-long pile groups.The consolidation settlement of soil and the side friction resistance of the pile body can be increased by increasing preloading.Increasing the preloading time can increase the side friction resistance of the pile,reduce the settlement of pile top and the axial force of the pile.The effect of preloading on the pile group is better than on the single pile.The better the consolidation degree is,the better the bearing performance of the super-long pile groups.For the silty clay,clay and muddy silty clay,the consolidation of the foundation is basically completed when the preloading time reaches about 90 days and 180 days respectively,and the preloading no longer changes the mechanical index of the soil.