To enhance the temperature and salt resistance of fracturing fluid polymers in seawater, acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 4-acryloylmorpholine (ACMO), and the nonionic hydrophobic monomer octadecyl polyoxyethylene ether methacrylate (OEMA) were used as monomers to prepare seawater-based instant temperature-resistant polymers (PAOAA) via aqueous solution polymerization. The structure and morphology were characterized using FTIR, 1H NMR, and SEM; PAOAA"s performance as a fracturing fluid was tested through thickening and rheological experiments. The results indicate that PAOAA can be dissolved in seawater within 2.0 minutes. The apparent viscosity of a 0.8% PAOAA solution is 108 mPa·s, demonstrating strong temperature and shear resistance. There is little difference in the endpoint viscosity at 100 and 170 s-1 shear rates, with values consistently over 50 mPa·s at different temperatures. The sulfonic acid groups in monomer AMPS shield salt ions in seawater, enhancing the water solubility of PAOAA; Heterocyclic ACMO enhances the rigidity of PAOAA molecular chains; The nonionic hydrophobic monomer OEMA allows PAOAA to form associative microdomains, improving its temperature resistance. The combined effects of these monomers result in the instantaneous and temperature-resistant properties of PAOAA.