Most studies on the operation policy for AS/RS concluded that the class-based storage policy has better performance than random storage policy does. However ASRS performances are examined only with the assumption of fixed production quantity in the studies. It is true that production quantity of each item changes frequently in practice. If an ASRS keeps the current storage policy regardless of production quantity variation, the performance of present storage policy will be worse. The effect of production quantity variation per product between 10 and 80% with random storage policy and class-based storage policy with reassignment and relocation are studied. The results are compared with both of the randomized and class-based storage policies without reassignment nor relocation cases. A typical ASRS system is developed using GPSS/PC for operation policy evaluation purposes.