The invention belongs to the field of chemical synthesis, and relates to a preparation method of a temperature-resistant and salt-resistant copolymer. The method comprises the following steps of sequentially adding water, an additive, acrylamide, a functional monomer and a template substance into a reactor, adding inorganic base to adjust the pH value of a polymerization system, adding an initiator to initiate a polymerization reaction, putting the polymerization system in a heat insulation environment, and stopping the reaction when the temperature of the center of the polymerization system is unchanged, thereby obtaining a polymer colloid; and crushing the polymer colloid into colloid particles, adding a hydrolysis agent for hydrolysis, and carrying out drying, crushing and screening toobtain the copolymer, wherein the template substance is polyacryloyloxyethyltrimethyl ammonium chloride or polymethacrylamidopropyltrimonium chloride; the functional monomer is a sulfonic acid derivative containing terminal alkenyl and a sulfonate derivative thereof; the molar ratio of the template substance to the functional monomer is (0.1-1) : 1; and the mole ratio of the functional monomer tothe acrylamide is (0.05-0.2) : 1. The components cooperate mutually; and the obtained copolymer is remarkably improved in temperature resistance and salt resistance.