Abstract: To solve the calculation problems of uneven composite rods and beams by the theory for the even isotropic material rods and beams，from the basic theory for the material parameter of the composite monodirection laminated plate，the theory and method to simulate composite rods and beams in FEA model are discussed in this paper，including how to determine the material parameters，flexural rigidity，moments of inertia to axis，neutral axis and section stress of the composite rods and beams．In addition，the correctness of the theory and method is verified by calculative cases．This theory and method have significant reference value in solving practical engineering problems．