The tensile deformation and fracture behavior of composite solid propellant were observed by in-situ scanning electron microscopy.The obtained microscopy images under different phase were analyzed by Digital Image Correlation Method(DICM).The microscopic deformation field and failure characteristics of composite solid propellants were obtained.The results show that DICM coupling with SEM is a ideal approach to measure and study the failure of propellant on a grain scale and it can provide the experimental evidence for numerical simulation.