Abstract: To discover novel aphicidal compounds and provide more effective pest management solutions for agricultural production, the highly active insect kinin mimic Ⅳ-3, previously discovered by our research group, was selected as a lead compound. A total of 12 novel target analogs were designed by replacing the styrene moiety of the cinnamoyl group at the N-terminus with a pyridine ring fragment through active substructure stitching while maintaining the tetrapeptide structure, and prepared using the Fmoc solid-phase synthesis method. Their structures were confirmed by HRMS and ¹H NMR. The bioassay results showed that all the target compounds had aphicidal activity against A. glycines. The activity of Ⅱ-10 (LC₅₀ = 4.5 µmol/L) was superior to that of the lead compound Ⅳ-3 (LC₅₀ = 16.63 µmol/L) and the commercially available pymetrozine (LC₅₀ = 19.75 µmol/L). Preliminary structure-activity relationship analysis suggested that aphicidal efficacy is influenced by both the position and the type of substituents on the pyridine ring, with the 4-position substitution and CF₃ substituent proving most effective. This study provides valuable insights for the development of novel insect kinin-based aphicides.