A method for performing block management is provided. The method is applied to a controller of a Flash memory having multiple channels, where the Flash memory includes a plurality of blocks respectively corresponding to the channels. The method includes: obtaining at least one portion of a plurality of address-to-channel mapping relationships, for use of writing/programming operations; and according to at least one address-to-channel mapping relationship of the plurality of address-to-channel mapping relationships, programming at least one page of data into the Flash memory through at least one channel in a page mode. An associated memory device and a controller thereof are also provided.