Lanthanum aminobenzoate (LAB), cerium aminobenzoate (CAB), and lanthanum and cerium aminobenzoate (LCAB) were synthesized with p‐aminobenzoic acid, lanthanum nitrate, or cerium nitrate as raw materials to study the influence of different rare earth elements on the stability of rare earth stabilizers. The thermal stability of by CAB, LCAB, and LAB toward poly(vinyl chloride) (PVC) was studied. The results of Congo red test and thermal aging test showed when three rare earth stabilizers acted independently, the advantages and disadvantages of thermal stability are as follows: LAB > CAB > LCAB. However, in compound experiments, the thermal stability of composite stabilizers compounded by CAB or LCAB with zinc stearate, calcium stearate, or pentaerythritol (PE) was slightly better than that of composite stabilizers compounded by LAB. Among of them, when the compounding scheme was LCAB:zinc stearate:PE = 1:1:3, the thermal stability time reached 60 minutes; CAB:zinc stearate:PE = 1:1:3, the thermal stability time reached 50 minutes, compared with the rare earth stabilizer alone, the composite thermal stabilizer gave PVC samples better antidiscoloration performance and longer thermal stability time.