The charge compensation mechanism exerts a significant influence on the electrical properties of non-equivalent doped perovskite piezoelectric ceramics 2.5%Eu-doped 0.71PMN-0.29PT ceramics (The optimum d₃₃=1111pC/N for R) compensated by (i) creating A-site vacancy (VA) (ii) creating B-site vacancy (VB) (iii) changing the B-site cations ratio (R) (iV) self-compensation without specific charge compensation design (Reference) are fabricated via the solid-state reaction method. Positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler broadening spectroscopy (CDBS) are employed to characterize the defect structures in the ceramics, and the effects of defects on piezoelectric properties and relaxor behavior are analyzed. PALS and CDBS results indicate that A-site vacancies dominate in the VA sample, while B-site vacancies dominate in the other samples. Notably, VA and VB exhibit the highest concentrations of A-site and B-site vacancies, respectively, which confirms that the defect distribution is generally consistent with the designed charge compensation mechanisms. Compared to R and Reference, the VA and VB samples show higher room-temperature dielectric constants, resulting from a higher degree of local structural heterogeneity, but relatively lower piezoelectric coefficients. This abnormal phenomenon is associated with the higher concentration of oxygen vacancies that pin domain walls and inhibit piezoelectric responses in the material. The relaxor behavior of the ceramics was also affected by the charge compensation mechanism. The Curie temperature decreases, while the degree of relaxor dispersion increases in the order of R, Reference, VA, and VB, which is related to the interference of A/B-site vacancies on the long-range ordered structure. This study demonstrates that in Eu-doped PMN-PT ceramics, charge imbalance should be compensated by changing the B-site ions ratio for excellent piezoelectric properties, and by creating B-site vacancies to achieve superior relaxor behavior.