Biodiesel is one of the alternative fuels. Biodiesel can be made from palm oil and the other raw materials. This research studies the optimum condition of palm oil (RPO) production by methanolysis reaction of heterogeneust catalyst calcium Oxide (CaO) aided by microwave irradiation. In order to get optimum condition, pretreatment catalyst has been done in 500oC at 1 hour. FFA removal can be reduced until 0,2% by esterification . The result of biodiesel was analyzed by Gas chromatography to measure the total of methyl esters conversion. The optimum condition for transesterification was 400 watts and catalyzed by 5% of CaO of weight oil, have the yield of biodiesel 75,60% and the conversion of methyl esters 92%.