Abstract: The HDPE/glass spheres and the HDPE/CaCO₃ filled systems were taken as the investigated models, and the influence of the interfacial adhesion, the filler content and its particle size on the properties of filled HDPE composites and the crystalline morphology of their matrices was investigated by using scanning electron microscopy, infrared spectra meter, polarizing microscope, small angle light scattering, material universal testing machine, etc.The results show that in the higher interfacial bonding strength condition, the produced interfacial stress from the contraction of matrix in the composite injection molding can disturb the spherulites grrowving surroundings in the matrix,strain-induces the crystallization of matrix in the area surrounding the filler, and leads to forming the extended-chain crystal structure. Meanwhile, it was found that the properties of filled HDPE composites were also obviously changed, and that the interfacial bonding strength was an important factor in producing the strain-induced crystallization, controlling the multiphase crystallization and modifying the properties of the filled composites.