Abstract: Aiming to solving the problem of water resource shortage in apple orchard on terrace by reasonable allocation of water cellar, water cellars were optimally allocated based on the verification for water storage dynamic change in 0-200cm soil using WEPP model, to meet the water demand of Malus pumila Mill during its growth period in different typical years . The results showed that water storage in 0-200cm soil could be well dynamically and simultaneously simulated when the databases of soil and crop management in WEPP model were updated; The water cellar should be optimally allocated base on soil water dynamic variation in typical year, which could better meet the water demand of the Malus pumila Mill; The allocation of water cellar is 1150m³/hm² in typical dry years, 180m³/hm² in the normal years and 50m³/hm² in the wet years in loess hilly and gully region. This study provided a good water cellar optimal allocation method, base on soil water dynamic variation to meet the water demand of the Malus pumila Mill, for efficient utilization of the limited water resources.