Owing to the double bond of butadiene which is the main chain, ABS resin is easily oxidized by UV light and this results in the deterioration of impact strength, weatherability, and thermal stability. Therefore, to improve this demerit, n-butyl acrylate was used instead of butadiene for the synthesis of BAR(butyl acrylate rubber) latex, then ac-onitnle(AN) and styrene(ST) was graft-copolymerized onto it to make ASA(acryonitrile-styrene-acrylate) latex. For better crosslinking and grafting, TAIC(triallyl isocyanurate) and TAC(triallyl cyano-rate) was used as a crosslinking agent. The effects of the concentration of them on gel content and swelling index of BAR were studied. It was shown that the gel content was highest at 4% of TAlC and TAC. Additionally when the amount of TAlC and emulsifier were increased, particle size decreased in both cases. The time-conversion curves of ASA latex were alsoexamined. As the reaction temperature was increased, both polymerization rate and final conver-sion increased. The effects of the following parameters on graft ratio were investigated : 1)concentration of initiator and TAlC ; 2) monomer to polymer ratio ; 3) initial reaction tempera-ture. And the effect of the concentration of initiator on inherent viscosity of free SAN was also studied.