Considering the engineering background of high speed transportation systems such as maglev, vertical vibration of a flexibly connected double span beam is studied. The beam can be taken as two Euler-Bernoulli beams flexibly connected by an elastic joint and the model of it bearing moving distributed load with constant speed is then established. Duhamel integral as well as mode superposition method is applied to solve the dynamic responses of the beam. Numerical analysis base on different parameters such as the length of the train, the span of the beam and the velocity of the train are compared. The following conclusions are made:(1) the left span and right span’s dynamic responses is different so that each span should be analyzed separately; (2)the dynamic response of the beam is tied up with the factors such as the frequency of the beam, the moving frequency of the load and the relative bending stiffness of the joint.