A method for managing a non-volatile memory is provided. The non-volatile memory has a number of blocks, and each block has a number of sub-blocks. The method includes a number of steps. First, a last physical address is obtained. The last physical address corresponds to a sub-block which is close to another sub-block where data is newly stored. Next, it is determined, for each sub-block of at least one block, the validity of data being stored. The at least one block is at least one neighboring block of a block containing the corresponding sub-block of the last physical address. Then, a mapping table is produced according to the step of determining the validity of data.