The kinetics of inverse emulsion polymerization of sodium acrylate solution has been studied at 23-39℃ with Cobalt-60 Gamma initiation dilatometrically. The conversion-time curves are generally S-shaped. For maximum rate of polymerization, the following kinetic expression has been determined for the conditions investigated:,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42649340&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42649342&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42649341&type=,The overall activation energy for polvmerization rate(E,a,) is (16.7 kJ/mol)(23-39℃). The effects of dose rate, monomer concentration and emulsifier concentration on molecular weights of pdymers have been examined. Discussions on nucleation mechanism and kinetics have been taken.