NOVELTY - The device has methanol-catalyst storage tank (3) of pre-esterification reaction kettle (5) which is connected with multi-frequency ultrasonic reactor (8) that is connected with one end of oil pump. Other end of oil pump is connected with glycerin separating tank. Glycerol separating groove (11) is provided with outlets that are respectively connected with inlets. Product groove (13) is set with inlet and outlets that are respectively connected with rough tank and waste water tank (14). Bottom portion of rough tank is connected with fractionating unit (17).    USE - Device for producing bio-diesel oil for use in wastewater treatment system using ultrasonic radiation tube-type reactor.    ADVANTAGE - The mass transfer and heat transfer of the ester exchange reaction of the device can be enhanced reliably. The fast speed, high efficiency and continuous producing of bio-diesel by the device can be achieved easily. The simple operation of the device can be attained. The realization of the automatic control can be easy. The reaction time of the device can be shortened. The energy consumption can be reduced. The production capacity of the device can be improved effectively. The production cost of the device can be reduced.    DETAILED DESCRIPTION - The ultrasonic reactor is composed of four independent ultrasonic reaction tanks through the overflow pipe that are connected in series. The raw material tank is provided with the rotor flow meter and pipeline. The adjustable rotating speed tank is provided with the mechanical stirring element. The hot water tank is provided with the thermoelectric couple and the temperature controllable heating unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the device for producing bio-diesel oil. (Drawing includes non-English language text)    Methanol-catalyst storage tank (3)    Pre-esterification reaction kettle (5)    Multi-frequency ultrasonic reactor (8)    Glycerol separating groove (11)    Product groove (13)    Waste water tank (14)    Fractionating unit (17)