A compression method and a compression system for display frames of QFHD (quad full high definition) resolution are provided and applied to the image encoding/decoding environment of the H.264/AVC image encoding standard of the QFHD resolution and the effective dictionary base compression and de-compression algorithm, the image data compression rate can be tremendously raised at the resolution of 1080 HD (High Definition) content and the average memory data rate is greatly decreased. Hence only a bus with a lower frequency as 57 MHz can be done for the real-time of the resolution of 1080 HD content.