A method for giving a read command to a flash memory chip to read data to be accessed by a host system is provided. The method includes receiving a host read command; determining whether the received host read command follows a last host read command; if yes, giving a cache read command to read data from the flash memory chip; and if no, giving a general read command and the cache read command to read data from the flash memory chip. Accordingly, the method can effectively reduce time needed for executing the host read commands by using the cache read command to combine the host read commands which access continuous physical addresses and pre-read data stored in a next physical address.