Method for controlling memory array of flash memory, and flash memory using the same

A control method for a Flash memory array and a Flash memory is disclosed. The Flash memory array includes a plurality of blocks which are classified into groups and each group includes at least one block. The control method includes the steps of: recognizing an attribute of data transferred from a host, obtaining a storage group selected from the groups based on the attribute of the data, and storing the data into the blocks of the storage group and thereby the blocks of a same group store data of a same attribute; and performing a valid data collection, restricted to the blocks belonging to a same group, to release blocks of space.