A memory device including a memory unit and a control circuit is provided. The memory unit includes a plurality of memory banks. The memory banks are at least divided into a first group and a second group. The control circuit is coupled to the memory unit. The control circuit is configured to perform a first refresh operation on the first group and the second group. When the control circuit performs the first refresh operation on one of the first group and the second group, the control circuit performs a second refresh operation on a victim row of the other one of the first group and the second group. In addition, a method for refreshing a memory device is also provided.