NOVELTY - Producing a biodiesel stock oil comprises removing a solid material in oil using oil milking process, determining a sulfuric catalyst using a central composite design based on response surface method, removing phospholipids and free fatty acids in the oil, obtaining phosphatide content with greater 40 parts per million from Hevea brasiliensis, including the methanol based on oil weight comparison, removing the phosphatide content with lesser 10 parts per million through the esterification reaction, and removing the methanol and moisture in the oil.    USE - The method is useful for producing a biodiesel stock oil (claimed).    ADVANTAGE - The method is able to increase the yield of biodiesel stock oil, effectively removes the phospholipid content in the oil through the oil milking process, and can prevent the environmental pollutant by reducing the phosphorus content discharge.    DETAILED DESCRIPTION - Producing a biodiesel stock oil comprises removing a solid material in oil by an oil milking process, determining a sulfuric catalyst using a central composite design based on response surface method (RSM) and methanol amount, removing phospholipids and free fatty acids in the oil by performing an esterification reaction in presence of the sulfuric catalyst according to the determined methanol amount without the degumming process, obtaining phosphatide content with greater than 40 parts per million from Hevea brasiliensis, comparing the oil weight (0.6-1 wt.%) according to the central composite design in which the sulfuric catalyst is selected based on RSM, including the methanol based on oil weight comparison (20-30 wt.%) within the reaction system, removing the phosphatide content with less than 10 parts per million through the esterification reaction, removing the methanol and moisture in the oil, where the methanol and moisture removing step is performed by separating an upper layer corresponding to the methanol layer in bulk phase and a lower layer corresponding to the oil layer in which phospholipid is removed through spalling by gravity and centrifuge; and by removing the methanol and moisture from the oil layer through the vacuum evaporation.