In order to alleviate the CaF2 scale blockage of reverse osmosis membranes, poly(epoxysuccinic acid) (PESA) was modified using 2-phosphobutane-1,2,4-tricarboxylic acid (PBTCA) and tyrosine (Tyr), and the scale inhibitors, PBTCA-PESA and PBTCA-Tyr-PESA, were prepared.The structure and thermal stability were determined by infrared spectroscopy and thermogravimetric analysis. The static and dynamic experiments were used to test their scale inhibition performance, and the results showed that: in the static experiment, the scale inhibition rates of PBTCA-PESA and PBTCA-Tyr-PESA on CaF2 were 94.92% and 98.72%, respectively, at the dosage of 200 mg/L, which had the ability of complexing Ca2+ and prolonged the time of crystallization induction; in the dynamic experiment, the decrease in the specific flux of the membrane was 34% and 27%, and the decrease in the specific flux of the membrane was 1.5 times higher than the specific flux of the membrane. In the dynamic experiment, the membrane specific flux decreased by 34% and 27%, showing better performance in dispersing CaF2 and effectively alleviating the membrane clogging.XRD and SEM characterization showed that PBTCA-PESA and PBTCA-Tyr-PESA could cause the irregular growth of CaF2 crystals, destroying the formation of crystals and altering the crystalline shape, and the main scale inhibition mechanisms were dispersing effect, crystal lattice distortion, and chelating effect.