0.85Pb(Zn1/3Nb2/3)O3-0.10BaTiO3-0.05PbTiO3 (abbreviated as PZN-based ceramics hereafter) ternary system ceramics with Zn2+ deficiency were synthesized by the columbite method. The effect of deficient Zn2+ on phase structure, ordered micro-region size and dielectric properties was investigated in detail. The analysis of Raman scattering spectra demonstrated that Zn2+ deficiency sharply enlarged the ordered micro-region size. Zn2+ deficiency significantly increased the dielectric constant, and decreased the diffusion degree of phase transition. There is a close correlation between effective ordered micro-regions size and dielectric properties for the PZN-based ceramics.