Abstract：A novel bio-based epoxy resin system with rosin-sourced acid anhydrides was established by formula design and selection according to the resin film’s forming performance and state with different storage time. The formula involves epoxy resin/curing agent/accelerator with mass proportion of 100/60/3-4. The curing property and the relationship between viscosity-temperature-time of resin were characterized by dynamic or steady state DSC analysis and cone plate viscometer, respectively. The results show the resin system can be cured at the range of 120-140℃, and the range of hot melt prepreg temperature is 60-85℃ with the viscosity from 1500mPa·s to 5000mPa·s. The processing time of hot melt prepreg is about 180min at 70℃. The curing mechanism of bio-based resin was also investigated through the samples with different curing time by IF and DSC.