A kind of three-tier hybrid plasmonic photonic crystal which is respectively constituted by a metal layer of silver (Ag), a low refractive index dielectric layer of SiO2 and a two-dimensional photonic crystal layer, is proposed. A clear plasmonic transverse-magnetic (TM) bandgap can be formed in this hybrid plasmonic photonic crystal. The defect cavity is constituted by introducing a unit cell defect in the center of the two-dimensional photonic crystal layer. The volume of the hybrid plasmonic photonic crystal micro-cavity is based on nano-scale, which is much less than the conventional optical micro-cavity, and the photon energy is well confined in the low index layer, so light can be limited at deep sub-wavelength scale. With some different structure parameters, the numerical analysis method of three-dimensional finite difference time domain (3D-FDTD) is used to analyze the characteristics of this hybrid plasmonic photonic crystal. The analysis indicated that this kind of nano micro-cavity has an ultra-small mode volume of 0.0141 (λ/n)3 and an ultra-high Q/V.