The invention discloses a polyacrylamide surfactant and a preparation method thereof. An acrylamide monomer and an anionic-nonionic composite surfactant monomer (N-alkyl-N-acrylamide polyoxyethylene ether sulfonate) are copolymerized to prepare the polyacrylamide surfactant under the action of a solvent. The surfactant has the viscosifying effect of aqueous solution of polyacrylamide polymer and the effect of reducing surface/interfacial tension of the anionic-nonionic composite surfactant, the temperature resistance and salt resistance of the polymer are improved due to introduction of sulfonic acid anions and nonionic polyoxyethylene ethers, and the invention can be applied to the fields of tertiary oil recovery, coating industry, water treatment and the like.