Pt/La 2O 3/Pt MIM (Metal-Insulator-Metal) capacitor was fabricated and its electrical characteristics were evaluated. Relation with voltage coefficients of the C-V curve (α and β) and 1/C and J was investigated. It was found that a has a strong correlation with 1/C, while β has no obvious correlation. Annealing temperature dependence of the leakage mechanism was studied. It was found that, under low electric field, the conduction is governed by Schottky, while, under high electric field, the conduction is Fowler-Nordheim (F-N) type. With high annealing temperature at 500°C, Poole-Frenkel (P-F) conduction appears between the Schottky and Fowler-Nordheim electric field regions.