Abstract: Aliphatic bismaleimide(HMDA-BMI) was used to copolymerize with 4,4’-bismaleimide diphenylmethyene (BDM) for preparing a matrix resin with low viscosity and good processing. When the molar ratio of HMDA-BMI to BDM is 1: 1, the viscosity-temperature test result shows that the viscosity of the HMDA-BMI-BDM system can be reduced to about 0.5 Pa·s, and the temperature range of the low viscosity platform is between 85-175℃. The viscosity-time result shows that the suitable mold filling temperature of the modified system is 130-145℃, and the obtained modified matrix HMDA-BMI-BDM resin is suitable for RTM. The curing process determined by the DSC method is 160℃×2 h+180℃×2 h+200℃×2 h+230℃×4 h. FTIR result shows that the modified system can be completely cured according to this process.The results of DMA and TG analysis show that the heat resistance of the modified system remains basically unchanged. The tensile strength and flexural strength of the modified system reaches 80.1 MPa and 116 MPa, respectively.