The effects of the concentration of link transfer agent (dodecyl mercaptan) and initiator (benzoyl peroxide) on monomer polymerization conversion rate and viscosity were studied, and  the internal connection between them was found out. The dosage of link transfer agent and initiator under suitable conditions to obtain a more satisfactory effect. As the amount of the link transfer agent changes, the viscosity of the resin has different degrees of influence, and the conversion rate is more dependent on the dosage ratio of dodecyl mercaptan to benzoyl peroxide. The mechanism of link transfer reaction was discussed, which provides a basis for the synthesis of low-viscosity acrylic resin.