An amphiphilic macro-monomer of allyl polyoxyethylene-12 ether with butyl-end group (AE12B) was synthesized, and its chemical structure was characterized. AE12B and the other two macro-monomers with different hydrophobic and hydrophilic groups were copolymerized with acrylamide to prepare the novel comb-shaped acrylamide copolymer (CPAM) through aqueous free radical polymerization. The solution properties of CPAM with different side-chain lengths were studied and compared with those of partially hydrolyzed polyacrylamide (HPAM). The experimental results show that the obtained CPAM, compared to HPAM, exhibited a dramatic enhancement in the heat- and salt-resistant properties. In addition, the increase of the side-chain length and the amount of hydrophobic groups in the side-chain improved the thickening properties of CPAM solution under high temperature and high mineralization conditions. Among the investigated macro-monomers, AE12B was optimized for the enhanced thickening properties of the CPAM solution.