The fluid dynamic characteristic of vortex flow washing in a fruits and vegetables washer unit with U-shaped structure was investigated by three-dimensional Computational Fluid Dynamic simulation (CFD). The single vortex flow formed by longitudinal and transverse water jet in washer unit was simulated at different flux rates of longitudinal and transverse water jet. The vortex flow dynamic characteristic in water unit and the effect of vortex flow on strengthening turbulent washing were discussed. The simulation results shows that flux rate has a dominant effect on vortex flow spacious distribution and intensity; the interaction between longitudinal and transverse water jet is controlled by location of longitudinal jet; when longitudinal jet appears near transverse jet the interaction occurs significantly and is benefit to transport washing flow towards outlet; vortex flow region appears high turbulent intensity to enhance the washing micro dynamic.