Advancing the development of novel materials or architectures for random access memories, coupled with an in-depth understanding of their intrinsic conduction mechanisms, holds the potential to transcend the conventional von Neumann bottleneck. In this work, a novel memristor based on the Sb2(S,Se)3 material with an alloy of S and Se was fabricated. A systematic investigation of the correlation between the Se/(S + Se) ratio and memristive performance revealed that Ag/Sb2(S,Se)3/FTO memristive behavior is uniquely associated with the formation and disruption of anion vacancies and silver filaments. The resultant Ag/Sb2(S,Se)3/FTO memristor devices demonstrated good resistive switching, with durability surpassing 3 × 104 cycles, showcasing multilevel conductivity states. Furthermore, these devices successfully emulated the synaptic functionality. This research has established the foundation for the intrinsic conduction mechanisms of antimony chalcogenide memristor artificial synapses.