The vibration noise control is critical in engineering fields and the phononic crystal provides a new mean to control the vibration noise. The band gap structure of one dimensional phononic crystal is studied in this paper. By using the equivalent masses method we obtain the band gap structure which depends on M, m and β, the influences of initial frequency of vibration band gap via the material density, the diameter of rod and the lattice constant are analyzed. The results show that the low-frequency broadband gap characteristic is obtained by increasing M and reducing m, β. The initial frequency of vibration band gap decreases as the metal material density, the diameter of metal rod or the lattice constant increase. Some conclusions from numerical calculation are examined by the vibration experiment.