A method for caching and reading data to be programmed into a storage unit, performed by a processing unit, including at least the following steps. A write command for programming at least a data page into a first address is received from a master device via an access interface. It is determined whether a block of data to be programmed has been collected, where the block contains a specified number of pages. The data page is stored in a DRAM (Dynamic Random Access Memory) and cache information is updated to indicate that the data page has not been programmed into the storage unit, and to also indicate the location of the DRAM caching the data page when the block of data to be programmed has not been collected.