The invention provides a hydrophobic association polymer disclosed as Formula (I), wherein y=0.001-0.2, z=0.03-0.2, and x+y+z=1; the A is a monomer unit of hydrophobic monomers; and the viscosity-average molecular weight of the hydrophobic association polymer is 0.5-1.5 million. Compared with the prior art, the hydrophobic association polymer is composed of three units; the hydrophilic unit is formed by copolymerization in which acrylamide participates, and can provide hydrophilic groups for the hydrophobic association polymer; the hydrophobic unit is formed by copolymerization in which hydrophobic monomers participate, and can provide hydrophobic side groups for the hydrophobic association polymer; various hydrophobic side groups generate a hydrophobic association action in water, thereby forming a space network structure; (not necessarily by posthydrolysis), the sodium acrylate unit can increase the solubility of the hydrophobic association polymer; and under the combined actions of the three unit, the salt resistance and shear resistance of the hydrophobic association polymer are enhanced.