In order to study the ultimate bearing capacity of jack-up platform pile boot in the clay, the Abaqus pile boot-soil model is established, and the penetration process of the pile boot is simulated by Arbitrary Lagrangian-Eulerian (ALE) method. Three data processing methods of large-value method, middle-value method and small-value method are put forward, and the formulae for estimating the bearing capacity of pile boot are fitted. The simulation results are compared with those of the SNAME formula, and the feasibility of ALE method to simulate the penetration of the pile boot is proved. Considering the safety of the practical engineering, in order to modify the calculation result of SNAME formula and make it more consistent with that of ALE small-value method, a reduction method is proposed for the calculation formula of SNAME.