In order to develop the new high-performance tribomaterials for mechanical and electrical micro-devices, the influence of adding thermoplastic elastomer (TPE) on the mechanical and tribological properties of vapor-grown-carbon-fiber (VGCF) filled polybutylene telephthalate (PBT) composites (VGCF/PBT) was investigated. In this study, three types of functionalized TPE based on styrene butadiene elastomer: epoxy group grafted SBS (SBS-EP), hydroxyl group grafted SEEPS (SEEPS-OH) and amine group grafted SBBS (SBBS-NH₂) were added with PBT and VGCF/PBT composites. These composites were compounded with a twin screw extruder and injection-molded, and their morphology, tensile, impact and tribological properties were evaluated. The internal structure of the ternary composites (VGCF/PBT/TPE) was changed by the addition of TPE and VGCF. Moreover, the size of dispersed TPE particles changed with the types of functionalized TPE. The influence of the addition of TPE on the mechanical and tribological properties of VGCF/PBT was differed from each property item. Izod impact properties and wear resistance were remarkably improved with the addition of various functionalized TPE, however, the tensile properties and frictional coefficient were slightly changed by the addition. From the relation between various properties and internal structure of these ternary composites, it was found that the tensile elongation at break, izod impact strength and specific wear rate correlate closely with the size of dispersed TPE particles. It follows from these results that it may be possible to develop the new tribomaterials with sufficient balances of mechanical and tribological properties for micro-devices.