Abstract: By means of optimization of parameters such as packer’s slide-sleeve size, bleed-off area of sand port, packer-release travel of each packing-off, back-flush channel, this paper illustrates the con figuration and mechanism of QHY341 high pressure hydraulic compression fracturing packer. It has the fol lowing configuration features:partial sub-assembly, double liquid cylinders, 2-element packing seal, direct jointing to sand-port, and thus posses the advantages of simple structure, convenient seating and seal ing, small load when conducting step by step packer release, smooth back flush, easy stuck-release, resis tant to large pressure differential, capable of fracturing multiple layers at one operation, etc.. UP to now, the multiple layer fracturing packer has been used successfully for fracturing 9 layers in 6 wells.