Free radical solution polymerization of heptadecafluorodecyl acrylate (HDFDA) and heptadecafluorodecyl methacrylate (HDFDMA) was carried out by using 2,2'-azobisisobutyronitrile (AIBN) as the initiator in supercritical carbon dioxide (scCO2). We performed solution polymerization with changing initiator concentration, temperature and polymerization time to study the polymerization kinetics. A nonlinear least square method and dead-end theory were used to determine the constant, K (K=(kp√f )/√fdkt) and initiator decomposition rate constant (kd) from experimental data. kd was measured as 3.77×10-5 s-1 at 62.7 ℃ for poly(HDFDA) and 2.71×10-5 s-1 at 62.5 ℃ for poly(HDFDMA), respectively, by nonlinear least square method.