Three kinds of silicon-containing bismaleimide (4,4'-Bismaleimido phenoxy silane) monomers were synthesized and added through blending to general epoxy system for the study of their applications as reactive flame retardants. The thermal analysis of the BMI monomers in bisphenol type epoxy system had been discussed. An increase in the BMI contents decreased the storage modulus and gloss-transition temperature and slightly reduced the mechanical strength of the epoxy blends. Although the initial pyrolysis temperatures of all the blending systems gradually decreased as the silicon-content increased, all the silicon-containing epoxy systems still had good thermal stability and the flame retardancy was promoted significantly by increasing contents of BMI. The LOI values of all the blend types were increased to about 30 as the BMI concentration reached 20%.