For researching the flow distribution of squids jetting process,and providing theoretic basis for biomimetic robot,the numerical simulations of this process were studied by CFD. A simplified body of squids was modeled,and the mantle motion during escape-jet locomotion was explicitly included into the simulations by using a deforming mesh. By solving the 2D-axisymmetric,incompressible,laminar,unsteady Navier-Stokes equations,different vortex evolution behavior was observed depending on different mantle contraction rate and jet diameter,and the exiting condition of the critical vortex ring,the formation number L/D = 4,was verified. The calculations of corresponding instantaneous forces during the ejecting have also been carried out. The results show that this model is suitable to simulate jet process of squids and the numerical results are in satisfactory agreements with the experiment data.