It is reported herein that the interfacial adhesion between binder and filler has distinct effect on mechanical properties of propellant. The tensile fracture progress of propellant （nitrate ester plasticized glycidyl azide polymer （GAP） / hexanitrohexaazaisowurtzitane （ε-CL-20） polyether propellant and polyethylene glycol （PEG） / octogen （β-HMX） polyether propellant） was monitored by in-situ tensile scanning electron microscope. In addition， the interaction strength between binder matrices and solid fillers was characterized by adhesion work and binding energy. The adhesion work was studied by inverse gas chromatography （IGC） and contact angle method， and the binding energy was calculated via molecular dynamics （MD）. Results shows that the dehumidification and fracture expanding progress of GAP/ε-CL-20 propellant are more serious than these of PEG/β-HMX propellant during stretching progress. GAP/ε-CL-20 propellant breaks when the elongation is more than 60% while PEG/β-HMX propellant breaks when the elongation is more than 80%. Besides， the adhesion work 70.69 mJ·m^-2 and binding energy 259.90 kJ·mol^-1 between GAP matrix and ε-CL-20 are both lower than the adhesion work 98.61 mJ·m^-2 and binding energy 335.65 kJ·mol^-1 for PEG/β-HMX system， suggesting that the poor interfacial adhesion between GAP binder matrix and ε-CL-20 is one of main reasons for inferior mechanical properties of GAP/ε-CL-20 propellant.