The bonding interface is the weak link of old concrete structure after repair, and it is an important factor affecting the bonding properties of the interface between repair mortar and concrete matrix. In this paper, AAS cement was used as cementitious material to prepare repair mortar. The effects of polyvinyl alcohol (PVA) latex powder and polypropylene (PP) fiber on the interfacial bonding properties and microstructure of alkali-activated slag self-leveling repair mortar (ASLRM) were studied by fluidity test, interfacial flexural tensile strength test, interfacial tensile strength test and microscopic test. The results show that both PVA latex powder and PP fiber can effectively improve the interfacial bonding properties of ASLRM. When the two are mixed, the interfacial flexural tensile strength of 28 d increases by 43.1%, and the interfacial tensile strength of 14 d increases by 69.9%.