To develop a high-performance ceramic-electrets, the effects of Ca2+-doping on polarization and charging characteristics of LaAlO3 (LAO) ceramics were investigated. The surface potential of Ca2+-doped samples, prepared to have a X= Ca/(La+Ca) = 0-5% (mol/mol), exhibited a volcano-shaped correlation with the X, reaching max. value of 3.7 kV at X ≈ 0.5%. This result suggests that "Ca-LAO" can become an excellent electret substrate and the optimization of the doping composition is effective in producing "Ca-LAO" electrets with a high surface potential.