Driect numerical simulation of self-propelled swimming of three dimensional bionic fish and fish school in a viscous flow in a tank are investigated.The swimming rule and the profile of 3D fish from previous experimental measurements of living fish are used in the study.A parallel software package for the 3D moving boundary problem is obtained, which combines the adaptive multigrid finite volume method and the methods of immersed boundary and VOF (Volume of Fluid).With the CFD package the results of the self-propelled swimming of a 3D bionic fish and fish school in a viscous fluid is obtained for the first time.