A decompression circuit includes a first decompression unit and a second decompression unit. The first decompression unit performs a first decompression operation on data to generate first decompressed data. The first decompressed data includes a plurality of literals and a distance-length pair. The second decompression unit receives the first decompressed data, and sequentially performs a second decompression operation on the literals and the distance-length pair to generate second decompressed data. After the second decompression unit receives the distance-length pair from the first decompression unit and before the second decompression unit completes decompressing the distance-length pair, the second decompression unit transmits data required for the subsequent first decompression operation performed by the first decompression unit to the first decompression unit according to the distance-length pair.