The structure of double moisture removal suction slot in a final stage hollow vane was investigated using two-phase numerical simulation methods. Two types of suction slots configuration were designed according to the moisture removal suction mechanism. The flow filed of a steam turbine stage with employ double moisture removal suction slots was calculated. The moisture field and pressure field at different span wise were compared for the two types of cases. It is pointed that the moisture removal effectiveness and its influence on steam flow field should be evaluated synchronously. The Structure of case A had the ability to the treatment of steam and water film, which is superior to case B.