Abstract: The lumped parameter dynamic method of beam like members,the finite segment method,is analyzed and reviewed in detail.The dynamic equations of multibody systems are developed by means of Huston's method based on Kane's equations.The finite segment method is adopted to establish the models of the beam like members.The inertia effects of the nonlinear deformations of the beams are taken into account,and the mode transformation of relative displacements isintroduced into the calculating process to increase the efficiency.A typical experimental result verifies that the foregoing method can be used for dynamic analysis of multibody systems with the beams undergone nonlinear deformations.