Production process of biological diesel oil and apparatus

The invention discloses a production method of a biodiesel, including the following steps: (1) absolute methanol is mixed with a liquid basic catalyst, then mixed with raw oil, and pumped into a mixer; (2) the mixture is input into a tube-typed piston flow reactor which is enclosed within the scope of an ultrasonic generator; (3) the absolute methanol and the raw oil generate coarse biodiesel and glycerin under the action of the liquid basic catalyst; and (4) the coarse biodiesel is subjected to washing, separation and refining, and the biodiesel is obtained; the invention also provides a device for producing the biodiesel comprising a liquid basic catalyst/methanol tank, a metering pump, a mixer, the piston flow reactor and a glycerin separator which are sequentially connected, wherein, one end of the mixer is connected with an intake line of raw oil, and the glycerin separator is respectively output and connected to a glycerol gathering tank and a storage tank of coarse biodiesel; and the device also includ