Developing effective compatibilizers for multiple immiscible polymers is crucial for recycling and reuse of plastics due to environmental and economic concerns. In this study, we prepared a multi-phase compatibilizer PP-g-(MAH-co-St) by maleic anhydride (MAH) and styrene (St) dual monomers melt grafting PP. And PP-g-(MAH-co-St) shows effective compatibilization in the ternary blends based on 70 wt% polypropylene (PP), 15 wt% polyamide-6 (PA6) and 15 wt% poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS). Scanning electron microscopy (SEM) observation reveals that PP-g-(MAH-co-St) is an excellent compatibilizer for the PP/PA6/SEBS blends. As shown in Fig.1，with increasing the compatibilizer, the PA6 phase in PP matrix changes from dispersed particles partially encapsulated by SEBS to smaller particles incompletely encapsulated by SEBS, and then to isolate nanoparticles separated from agglomerated SEBS. The compatibilized blends exhibit enhanced mechanical properties. Compared with the uncompatibilized blends, the blend with 15% compatibilizer has superior mechanical properties with the yield stress, stress at break, strain at break, maximum stress and impact fracture energy improved by 23%, 696%, 363%, 68% and 220%, respectively.