As the number of ultra-deep wells increased, the static temperature is getting higher and higher at the bottom of the wells, which leads to the poor settlement of the cement. Due to the issue of “high-temperature failure” of traditional suspension agent, a hydrophobically associating polyacrylamide liquid suspension agent XFJ-W was prepared by free radical water-soluble polymerization using N,N-dimethylacrylamide (DMAA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), hydrophobic monomer A and hydrophilic monomer B through molecular design. The properties and the structure of XFJ-W were characterized and the performance of hydrophobically associating polyacrylamide suspension agent in cement slurry was evaluated. The results indicated that the suspension agent XFJ-W was excellent in heat resistance and it could maintain the sedimentation stability of the cement slurry. The top and bottom density difference of cement slurry could be controlled at 0.05 g/cm3 with the density of 1.90–2.36 g/cm3 at 100–180 °C (BHCT). In addition, the suspension agent XFJ-W has good compatibility in the cement slurry and has good compatibility with different retarders and fluid loss additives. There was no negative influence on the fluidity, thickening and fluid loss of the cement slurry. It has good application prospect and provides reference for the preparation of oil well cement suspension agent.