In order to provide accurate information for the composite material molding process,DMTA was used to investigate the isothermal curing kinetics of domestic TG800 carbon fiber/802 bismaleimide resin prepreg.The gelpoint could be confirmed by apperance of the inflection point of loss modulus "E" under constant temperature scanning.Using the curing reaction rate to define the increasing in storage modulus E′,the growth mode of reaction degree α in different isothermal stage was investigated and the curing kinetics model was established.Hsich’s non-equilibrium thermodynamic fluctuation theory and Avrami equation were used to analysis the activation energy.The results of Hsich’s theory indicated that the activation energy of TG800/802 prepreg is 49.5 kJ/mol.The results of Avrami equation shows that the activation energy at early stage of the isothermal stage is smaller than that in later stage,Besides,the higher isothermal temperature is,the lower activation energy will be.At early stage of 200 ℃ the activation energy of TG800/802 is 78.8 kJ/mol,which is less than 109 kJ/mol in later stage,and it decreases to 32.4 kJ/mol when temperature rises to 240 ℃.According to the calculated results of curing degree in different isothermal stages,the cure cycle “150 ℃/1 h+180 ℃/2 h+200 ℃/4 h” is proved to be feasible,which provides technical support for engineering application of TG800/802 prepreg.