The invention relates to a polymer clay stabilizer containing Beta-cyclodextrin structure and a synthesis method thereof, wherein the polymer clay stabilizer is used for restraining clay hydration swelling of an oil well. The technical scheme is as follows: the polymer clay stabilizer comprises the following materials and monomers in percentage by mass: 35-54.8% of acrylamide AM, 15-25% of sodium acrylate NaAA, 8-20% of 2-acryloyl-methyl-propyl sulfonate AMPS, and 0.2% of 2-O (propenyloxy-2-hydroxy-propyl)-Beta-cyclodextrin XBH; 0.02g of XBH and 2g of AMPS are added into a flask, and then 5.48g AM, 1.915g of AA and 0.585 g of NaOH are added into the flask, so a water solution with the monomer mass percentage concentration of 20% is prepared, and nitrogen is introduced into the water solution for 20 min; (NH4)2S2O8 solution and NaHSO3 solution are then added into the water solution while nitrogen is continuously introduced into the water solution for 10-20 min, and reaction is carried out at the temperature of 35 DEG C for 4-12 hours; and finally, the reacted solution is subjected to washing with absolute ethyl alcohol, smashing and drying to obtain AM / NaAA / AMPS / XBH quaternary polymer. The polymer clay stabilizer has good water solubility, viscosifying capacity, temperature resistance, salt resistance, anti-shearing capacity and clay-swelling restraining capacity, and reaches the swelling prevention rate of 84.37% towards sodium-montmorillonite.