A co-rotational formulation and numerical procedure for the dynamic analysis of a spatial beam is presented. The co-rotational formulation for static analysis starts off by using the co-rotated frame to separate the deformational motion from the total motion. The relationship between the variation of the deformational displacements and that of the total global displacements is established by the transformation and the rotation matrices. The tangent stiffness matrix of the element is obtained by applying the principle of virtual work. In this paper, we extend the technique to dynamic analysis by using the variation of internal work and external work. Several numerical examples are validated and presented for spatial beam to demonstrate the accuracy and the efficiency of this method.