Algal blooms in drinking water sources produce a large amount of algal organic matter (AOM), and AOM can react with chlorine to produce disinfection by-products (DBPs), significantly endangering the water quality. Thus, the vacuum ultraviolet/persulfate (VUV/PS) process was employed to remove AOM and reduce the disinfection by-products (DBPs) formation. The VUV/PS process demonstrated superior efficiency in AOM removal compared to UV/PS, VUV, UV, and PS processes, achieving removal rates of dissolved organic carbon (DOC) and UV₂₅₄ of 74.7% and 70.7%, respectively. Additionally, the removal rate of fluorescent organic matter surpasses 82.2%. PS dose and initial pH impacted AOM removal by influencing the transformation and concentration of reactive oxygen species (ROS). The primary ROS in the VUV/PS process were hydroxyl radicals (HO^?) and sulfate radicals (SO₄^?-), with steady-state concentrations of 4.78×10^-13 and 1.51×10^-11 mol/L, respectively. AOM was effectively eliminated by VUV photolysis and ROS oxidation, with VUV enhancing the efficiency of AOM removal by facilitating the generation and conversion of ROS. Additionally, during subsequent chlorination, the VUV/PS process significantly reduced the yield of DBPs and theoretical toxicity. In conclusion, the VUV/PS process exhibited significant potential for application in treating AOM-rich water.