Abstract:A wave propagation method for vibration analysis of multi-span fluid conveying pipe that based on Timoshenko beam model is presented in this paper. By imposing the continuity and force balance condition, the wave reflection matrices are obtained for clamped supported end, simply supported end and free end respectively. The recursive algorithms are proposed for reflection matrices of intermediate supports. The frequency characteristic equation is deduced by using wave-train closure principle for the pipe supported at two ends. Finally, the present method is applied to calculate the first five natural frequencies of a seven span, 40 meters long pipe at four different cases. The results show that the proposed method is suitable for computer coding and has a high degree of accuracy.