A method for storing data of an image frame into a frame buffer includes at least the following steps: dividing the image frame into a plurality of access units, each having at least one encoding unit, wherein each encoding unit is a unit for data compression; and performing the data compression upon each encoding unit of the image frame, and generating an output bitstream to the frame buffer based on a data compression result of the encoding unit. A processing result of each access unit includes each output bitstream of the at least one encoding unit included in the access unit; a plurality of processing results of the access units are stored in a plurality of storage spaces allocated in the frame buffer, respectively; and a size of each of the storage spaces is equal to a size of a corresponding access unit.