This invention provides a homogeneous phase method for continuously manufacturing biodiesel oil. The method comprises: (1) mixing natural grease or waste fried oil, methanol, alkali metal hydroxide and an organic solvent that can homogenize the above mixed solution, sending into a prereactor, and preheating to obtain a homogeneous phase; (2) send ing into a tubular reactor, and continuously esterifying for 1-30 min to obtain biodiesel oil and glycerol; (3) distilling under normal pressure or reduced pressure to separate methanol and organic solvent, and separating by a separation tank to obtain biodiesel oil. The method makes grease and methanol completely mix in each other, thus largely increasing the reaction rate, shortening the reaction time, lowering the operation temperature, improving the equipment manufacture capacity. |