This paper treats the transmission of the shock waves in beam structures. Main contents are as follows. 1. The transmission of the flexural shock waves in an infinite beam is analysed from a standpoint of energy transmission and approximate solutions are obtained. 2. Approximate solutions are compared with exact solutions. When γ²/ a ² t >4, distributions of energy density in beams, envelopes of vibration amplitudes, and periods etc. obtained from exact solutions converge to the approximate solutions given in this paper. Even if the initial conditions of the beam, namely the initial shape and velocity shape of the beam, are arbitrary, approximate solutions of the beam response can be obtained easily by this method. 3. Shock wave transmission in structures composed of beams of different shape sections or corners are analysed using this method and compared with experimental results. In general, they were fairly in good agreement.