Abstract: Based on the flexible multibody dynamics theory,a flexible dynamical model for the simulation of a large marine diesel engine crankshaft is established through an in-house developed multibody procedure.In this model,the crankshaft is modelled by three dimensional solid elements based on the Absolute Nodal Coordinates Formulation (ANCF),and the main journal is modelled by beam elements based on the Finite Segment Method.By using the constraint equations,parts of the engine linkage mechanism are assembled,and the flexibility and nonlinearity of the spindle bearing are also considered.The constrained modal analysis and dynamic analysis of the crankshaft system are performed.Consequently,the bearing load and the displacement of the journal is calculated.In addition,the crankshaft's dynamic stress distribution is obtained,and the strength verification is also carried out.These results show that the ANCF based flexible multibody dynamics modelling and the implementation of simulation can provide theoretical basis for improvement and design of diesel engine.