This paper presents the technique that can considerably improve basicity and transesterification activity of calcined natural calcite. Calcined calcite was refluxed in water followed by the calcinations at 600 oC. The characterization results indicate that this procedure substantially increases both the specific surface area and the amount of basic site. Hydration and subsequent calcination also generates a new calcium oxide with less crystalline. ME content was enhanced to 93.9 wt% in 1 hr from 75.5 wt% of calcined calcite. The results imply that the active sites produced by the calination of hydrated sample at 600 oC have higher basicity than those generated from calcinations of fresh calcite at 800 oC. The present study provides new insights for improving catalyst activity by tailoring the preparation conditions.