AbstractTo explore the influence of reaction medium on the copolymerization behavior of acrylamide‐based copolymers, three types of copolymers (P(AM‐St)(ILs), P(AM‐MMA)(ILs), and P(AM‐AMPS)(ILs)) were synthesized by combining insoluble, slightly soluble, and easily soluble monomers with acrylamide in the 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF4) reaction medium. The reactivity ratio, Fourier transform infrared spectroscopy, 1H NMR spectroscopy, elemental analysis, and scanning electron microscopy were employed to characterize the copolymers' properties. The results indicated that in [BMIM]BF4 copolymerization, the reactivity ratio of AM and St in P(AM‐St)(ILs) decreased, the reactivity ratio of AM in P(AM‐MMA)(ILs) will increase. While the reactivity ratio of MMA will decrease. The reactivity ratio of AM in P(AM‐AMPS)(ILs) will increase and the reactivity ratio of AMPS will decrease. The distribution of AM and St segments in P(AM‐St)(ILs) molecular chains is more uniform and compact. When AM polymerizes with hydrophobic monomers (St) in [BMIM]BF4, its copolymer solution exhibits lower viscosity loss rates in temperature, shear, and salt resistance tests. Therefore, ionic liquids are more suitable as reaction media for the synthesis of hydrophobic‐modified polyacrylamides, which facilitate a more uniform distribution of hydrophobic monomers within the copolymer chains and exhibit enhanced resistance to temperature, salt, and shear stresses.