Chain transfer reactions are important side reactions in the radical polymerization of acrylates. Discrimination between interchain and intrachain transfer is still a challenge for the study of interchain transfer. A prepolymer, poly(benzyl acrylate) with hydroxy terminals (HO-PBzA), was designed and used in the reversible addition-fragmentation chain transfer (RAFT) polymerization of BzA to measure the interchain transfer degree, with benzyl N-carbazole dithiocarbamate (BCBD) as the RAFT agent. Liquid chromatography at critical conditions was used to separate and measure interchain transfer products and then BzA interchain transfer constants (Ctr) at different temperatures determined without other kinetic parameters. Experimental results showed that experimental parameters in RAFT polymerization, except the high dosage of BCBD, had no significant effects on the measured Ctr, which showed good repeatability. The Ctr of benzyl acrylate at 100-120 °C was in the order of 1-2×10-4 and the activation energy of Ctr was at 31.1 kJ.mol-1.