A new scheme of one-dimensional metal heterowaveguide array is proposed that the core layer of the metal waveguide is periodically modulated. Numerical results reveal that, periodic modulation of the core layer of metal waveguide induces the periodic modulation of the effective refraction index of the surface plasmon polaritons (SPP) in the waveguide, which opens up an SPP band gap around a certain waveband, such as waveband around 1550 nm. Further numerical results reveal that, the SPP mode resonance with high quality for example Q=556 can be obtained at some wavelength by introducing a proper defect waveguide layer. The results can be applied to the subwavelength Bragg reflectors, light emitters and filters, and could be also availabe for the future integrated optics.