A method for accessing a Flash memory and an associated Flash memory system are provided, where the Flash memory includes a plurality of blocks, each of the blocks includes a plurality of pages, and each of the pages includes a plurality of sectors. The method includes: receiving a page of data from a host; encoding a first portion of the page of data by a randomizer that operated under a first seed to generate a first encoded data; encoding a second portion of the page of data by the randomizer that operated under a second seed to generate a second encoded data, wherein the first seed is different from the second seed; and storing the first encoded data and the second encoded data to the Flash memory. An associated method and an associated Flash memory system are also provided.