The scaled model pump of TJ04-ZL-02 hydraulic model, which has been applied on the Tianjin same test-bed for South-to-North Water Transfer Project, was simulated base on fine calculation for tip region flow field and SST k-ω turbulence model, and flow field structure for tip leakage vortex as well as filed dynamic characteristics were studied. Numerical calculations and experimental results show that numerical simulations for clearance leakage and boundary layer flow based on SST k-ω turbulence model are relatively accurate. The power arose from tip leakage vortex is regard as differential pressure between the pressure side and the suction side of blade. For the pressure difference of blade leading edge is the largest, velocity of tip leakage flow is higher. The pressure difference between blade pressure and suction side is increased gradually with the increase of blade chord coefficient λ, and clearance leakage flow velocity as well as leakage vortex strength is decreased gradually. The local low pressure of blade tip region mainly occurs on vortex region of separated vortex near the pressure surface, as well as tip leakage vortex region at the lower part of blade suction side. The local low pressure region of blade suction side is getting further away from blade suction side with the increase of blade chord coefficient λ. The local low pressure region of blade rim near blade pressure side is mainly caused by separated vortex which is induced by blade tip corner， and the low pressure near suction side of blade is resulted from tip leakage vortex, and the process reveals the flow characteristic of tip leakage vortex for axial flow pump.