This paper applies moving mesh technology to the numerical simulation analysis of computational fluid dynamics（CFD） based on harmonic mapping theory.It deduces renewal process of the solving domain when moving mesh technolog deals with problems of large deformation,and the corresponding program flow diagram is given.It solves the problems of grid large deformation which the traditional fixed grid is unable to simulate.It uses the multi-physical coupling analysis software COMSOL Multiphysics 4.0a to couple the moving mesh equation with controlling differential equation,and simulates the movement of the oil inside the swaying tank. The numerical simulation show that moving mesh technology can simulate the situation of solving domain’s large deformation truly.In the process of simulation,the number of the nodes and grids in the fluid domain do not increase,it just changes the shape of the grids,so that,the moving mesh method dose not increase the spending of computer resources extra.