A method of data migration for independent storage device expansion and adaptation is disclosed. The method migrates user data of a first storage unit being pre-expanded or pre-adapted to relevant regions of a second storage unit being post-expanded or post-adapted in multiple batches and includes the following steps. A number corresponding to a start data stripe of the first storage unit is provided in each batch. A data stripe migration quantity is determined. Data stripe user data of the determined data stripe migration quantity subsequent to and including the start data stripe of the first storage unit is duplicated and stored in relevant regions of the second storage unit. Subsequent to duplicating and storing each batch, the original user data of data stripes of the determined data stripe migration quantity subsequent to and including the start data stripe of the first storage unit remains undamaged.