A count table maintenance apparatus for maintaining a count table referenced to apply a backward adaptation to a probability table. The count table maintenance apparatus includes a count data access interface, at least one buffer, and at least one count data updating circuit. The count data access interface determines a read address and a write address of the storage apparatus. The at least one buffer buffers at least one input count data, wherein the at least one input count data is derived from count data read from the count table according to the read address. The at least one count data updating circuit updates the at least one input count data read from the at least one buffer to generate at least one updated count data, and store the at least one updated count data into the storage apparatus according to the write address.