The invention discloses a high-temperature-resistant polymer for acidizing fracturing and a preparation method of the polymer. The polymer is prepared by polymerizing raw materials comprising the following components: acrylamide, methacrylamide, a cationic monomer, a temperature-resistant salt-resistant monomer, a molecular weight regulator, an initiator and water; wherein the total mass of all components except water is taken as 100%, the mass percent of the components are as follows: 20%-65% of the acrylamide, 5%-15% of the methacrylamide, 5-18% of the cationic monomer, 15%-55% of the temperature-resistant and salt-resistant monomer, 0.01%-0.5% of the molecular weight regulator, and 0.1-0.5% of the initiator, and the total mass concentration of all components except water is 20-35%. Thepolymer disclosed by the invention has good water solubility, acid solubility, instant dissolution, temperature resistance, shearing resistance and excellent thickening effect, and can be applied to the fields of acidizing fracturing construction, reinforced oil production operation and the like in oil exploitation at a temperature of 160 DEG C or above.