Engineered geopolymer composites (EGC) exhibit excellent tensile ductility and crack control capabilities, making it promising materials for concrete structure repair. However, EGC high cost and the lack of understanding regarding the bonding mechanisms between EGC and concrete have limited EGC widespread application. By using polyethylene (PE) fiber and domestically produced polyvinyl alcohol (PVA) fiber, hybrid PE/PVA fiber EGC (PE/PVA-EGC) were prepared and the bonding performance at EGC-concrete interface was investigated. Slant shear tests were conducted to explore the effect mechanisms of varying PE fiber content, hybrid PE/PVA fiber ratio, and precursor ratio on the interfacial bonding performance. Results indicate that increasing PE fiber content, PVA fiber replacement ratio, ground granulated blast furnace slag content and concrete strength can improve the interfacial shear bonding strength. Increasing the PE fiber content from 1.0% (volume fraction) to 2.0% improves the interfacial shear bonding strength of specimens by 13.24%. The interfacial shear bonding strength increases with higher replacement ratio of PVA fiber and the strength of matrix. The best bonding performance is observed when the existing concrete strength grade is C50. In conclusion, with an appropriate matrix strength, hybrid PE/PVA fiber can effectively enhance the interfacial bonding performance between EGC and existing concrete while controlling repair or reinforcement costs.