Poly(tert-butyl acrylate)(PtBA)telomer with tribromomethyl end group was synthesized by radical telomerization of tert-butyl acrylate(tBA)with CBr4 as telogen and 2

2′-azobisisobutyronitrile(AIBN)as initiator. The number-average molecular weight(Mn)of PtBA-Br telomers was determined by GPC and 1H NMR，and PtBA-Br telomers with Mn of 2730—9200 were obtained. The Mn calculated from 1H NMR spectrum matched well with the Mn

GPC results. In order to accurately control the molecular weight of PtBA-Br telomers，the chain transfer constant(Cs)of CBr4 was determined by using the Mayo equation and simulation，and the value was 1.11 at 60℃. When the ratio of telogen and monomer concentration was 0. 02，the Mn of PtBA-Br telomers at 60℃ was between 5940 and 6450 at increased conversion from 25% to 73%. The Mn values were consistent with simulation results and the molecular weight distributions were all under 1.70.