Abstract: The interfacial bonding between aramid fiber and epoxy resins cured by triethylene tetramine is usually very weak,which limits the aramid fiber composite application.In this work,silane coupling agents were used for the surface treatment-of the Kevlar-49 fibers,the interfacial strength was studied by means of single fiber pull-out tests.It turned out that the shear strength (τ₀)of interface,the energy of interface fracture (G₁)and pull-out friction (F_f) were affected by the structure of silanes.2^# was recognized to be the best one among the six studied silanes.After treatment with 2^# the G,increased from 45J/m² to 72J/m² and the friction force F^f/L,from 15cN/mm to 21cN/mm.