In order to alleviate the CaF₂ scale blockage of reverse osmosis membranes, poly(epoxysuccinic acid) (PESA) was modified with 2-phosphobutane-1, 2, 4-tricarboxylic acid (PBTCA) and tyrosine (Tyr) to obtain PBTCA-PESA and PBTCA-Tyr-PESA. The static and dynamic experiments were used to test the scale inhibition performance, and the results show that in the static experiment, the scale inhibition rates of PBTCA-PESA and PBTCA-Tyr-PESA on CaF₂ are 94.92% and 98.72%, respectively, at the dosage of 200 mg/L, which possess the ability of complexing Ca²⁺ to prolong the time of crystalline induction; and in the dynamic experiment, the decrease rates of the specific flux of the membrane are 34% and 27%, showing better performance in dispersing CaF₂ and effectively alleviating membrane blockage. XRD and SEM characterization show that PBTCA-PESA and PBTCA-Tyr-PESA can cause the irregular growth of CaF₂ crystals, destroy the crystal formation and change the crystalline shape, and the main scale inhibition mechanisms are dispersive effect, lattice aberration, and chelating effect.