Abstract: Hydrophobic association hydrogels (HA-gels) with high mechanical strength were successfully prepared through micellar copolymerization of acrylamide (AM) and small amount of octylphenol polyoxyethylene acrylate (OP-4-AC) in an aqueous solution containing sodium dodecyl sulfate (SDS). On the basis of the micellar copolymerization theory, the statistical molecular theory of rubber elastic, the MooneyRivlin theory, and using uniaxial stretching data, formation mechanism of crosslinked network structure of HA-gels were investigated. Results show that the formation mechanism mentioned above could be characterized with ratio of SDS micellar concentrations in the initial solution to the effective network chain density of HA-gels.