Aiming at the hydropower station of high head, large flow and long diversion tunnel,and that the conventional type can not meet the design requirements by the effect of terrain and geological conditions on surge shaft, taking Boxianglin hydropower station for example,the paper compared the emergency gate and butterfly valve scheme and a variety of surge shaft types.Through the surge shaft structure calculation and hydraulic calculation,it demonstrated the reasonability of design of surge shaft by combining the emergency gate with open-air pool.The results show that the combination of emergency gate and open-air pool,the surge shaft has the advantages of the emergency gate and water chamber surge shaft,higher safety and reliability,convenient management and maintenance, effective reduction of surge wave height,decrease of surge height, save of amount of work, reduction of investment,This kind of surge shaft has economy and applicability,and can effectively solve the problem of surge tank design under special topographic and geological conditions.The result has important reference value for the design of surge shaft.