Based on ABAQUS software, this paper adopts the coupled Eulerian-Lagrangian (CEL) analysis to simulate the impact of the manifold framework into water. According to the characteristics of the manifold framework bearing external force during impact, its local structure (I-beam) is selected to build the numerical simulation model. The I-beam is simulated by a shell element, and the seawater area is discretized by the Eulerian grid. To simulate the influence of manifold mass, the paper utilizes the equivalent density method to modify the I-beam mass.The numerical model simulates the water entry process of the I-beam and calculates the velocity and stress time history of the key part.It gives the stress fields at different time points and discusses the influence of the initial velocity on the maximum Mises stress. This study lays a foundation for the analysis of the impact strength of the manifold framework.