Abstract: Polyphenylene sulfide (PPS) stands as a thermoplastic engineering material, renowned for its high strength and excellent stability. It has found extensive applications in both defense and civilian sectors. However, the intrinsic lack of toughness in PPS necessitates toughness enhancement for broadening its application scope, typically achieved through the incorporation of elastomers. In this study, a melt-blending technique utilizing a high-stretch chaotic flow rotor was employed to prepare hydrogenated styrene-butadiene-styrene block copolymer/polyphenylene sulfide (SEBS/PPS) composite materials. The research aimed to investigate the microstructural evolution of the materials under the influence of high-stretch external forces and analyze the impact of varying SEBS content on the mechanical properties of the PPS-based composite materials. The results indicate that with an increase in SEBS content, the impact strength and fracture elongation of the PPS-based composite materials exhibit an initial rise followed by a subsequent decline. When the SEBS content reaches 6wt%, the composite material demonstrates a ductile fracture behavior, achieving the highest impact strength and fracture elongation at 57.8 J/m and 6.1%, respectively. Microstructural analysis of the composite material reveals that within the SEBS content range of 0wt%-6wt%, under the action of the high-stretch blending rotor, SEBS particles exhibit smaller and more uniformly distributed sizes. The droplet morphology undergoes a transition to elongated rod shapes, indicating a brittle-to-ductile transformation and a significant improvement in toughness. In the composite material with 6wt%SEBS content, multiple silver streaks are induced upon impact, leading to shear yielding and exhibiting plastic deformation. Continued increase in SEBS content intensifies the aggregation behavior of SEBS, resulting in an enlargement of particle sizes and broader distribution. At this stage, numerous void regions appear at the two-phase interfaces, triggering the development of silver streaks and concurrently causing fracture failure in the composite material, leading to a decrease in impact strength.