A memory access method for selectively creating a simplified mapping table includes the steps of: selecting one of a plurality of partitions of an original mapping table so as to use one physical page address in a selected partition as a start physical page address; scanning each entry of the selected partition so as to search a randomly mapped entry in the selected partition; determining whether a memory space required for creating the simplified mapping table is smaller than a memory space required for the selected partition; and selectively storing the start physical page address, the number of the randomly mapped entries, and a logical page address and a physical page address recorded on each randomly mapped entry according to the determination result of the determining step so as to create a simplified mapping table.