Slick water hydrofracking is an important method for the efficient development of shale gas，but there are a series of challenges such as low viscosity，large freshwater consumption and slick water-to-gel transition，which limit its application on the hydrofracking of deeper（>3500 m）shale gas reservoirs. In order to solve these problems，an integrated thickener（HVFR）with high viscosity and drag reduction was synthesized by free radical polymerization of acrylamide and 2-acrylamido-2- methylpropanesulphonic acid. The solubility，thickening ability，drag reduction，proppant carrying capability and temperature and shear resistance of HVFR were studied. The results showed that the relative molecular mass of HVFR was 22.7 × 10⁶. HVFR thickener exhibited a rapid dissolution rate with thickening rate of 93% within 1 min，which was conducive to the online continuous mixing of fracturing fluid. HVFR thickener exhibited significant drag reduction performance. At a flow rate of 150 L/min，the drag reduction of slick water was higher than 70% for both low and high viscosity，and that was up to 68% for gel. HVFR thickener exhibited multifunctional properties and could be freely transited between slick water with low and high viscosity and gel by altering the concentration of HVFR. The cross-linked fracturing fluid based on HVFR displayed not only remarkable temperature and shear resistance，but also good proppant carrying capacity. The viscosity of cross-linked fracturing fluid could be maintained about 120 mPa·s after shearing 120 min at 120 ℃ and 170 s^-1，which met the requirement of fracturing operation.