Abstract: Gel viscosity in high-temperature was one of the most important properties about synthetic polymer-based fracturing fluid. In this paper, a hydrophobic associated polyacrylamide(HACA) with a rigid pendant group has been prepared using aqueous solution polymerization, and its rheology and heat stability are investigated. It is demonstrated that under 150℃ and shear rate 170 s^-1, apparent viscosity of 4wt% HACA aqueous solution is 99 mPa·s after 2 h; compared with normal polyacrylamide, both intrinsic viscosities are closed in dilute solutions, and HACA has greater apparent viscosity in semi-dilute solutions; related to normal polyacrylamide and that with only hydrophobic group or rigid pendant group, HACA has greater thickening ability, faster viscosity recovery and better heat stability. These results are helpful to preparation and research of synthesis polymer-based fracturing fluid.