The invention relates to aromatic mercapto barium salts, a preparing method thereof and applications of the aromatic mercapto barium salts. The general formula structure of the aromatic mercapto barium salts is shown in the description, wherein R is a C8-C12 straight-chain or branch-chain alkane. The preparing method for the aromatic mercapto barium salts includes (1) mixing mercaptobenzoic acid, diethylene glycol and a catalyst by stirring, heating to 70-150 DEG C, reacting with the vacuum degree ranging from -0.06 MPa to -0.09 MPa until no water drops in a water separator, cooling to room temperature, washing with water, and subjecting an oil phase to vacuum distillation to remove water to obtain diethylene glycol mercaptobenzoate, and (2) adding a C8-C12 aliphatic acid, a solvent and a proper amount of barium hydroxide, reacting at 90-110 DEG C for 2-4 h, dehydrating, and filtering to obtain a target product. Novel barium soap is adopted to improve thermal stability of PVC. Contrast experiments prove that the through applying compositions formed by the aromatic mercapto barium salts, the zinc soap and traditional stabilizing agents as PVC stabilizing agents, the initial-stage coloring stability and later-period stability of the PVC can be greatly improved and precipitation is inhibited so that the compositions have a good application prospect.