A series of poly(ether ester) based thermoplastic elastomers (TPEs) were synthesized by using dimethyl-2,6-naphthalenedicarboxylate (NDC) as hard segment, poly(tetramethylene ether glycol) (PTMEG) with a molecular weight of 1000 as soft segment and 1,4-butanediol (BDO) as chain extender. To improve the mechanical properties of TPEs, hyperbranched polyglycidol (HBP) were incorporated in the NDC units as soft segment together with PTMEG. The relative composition of HBP/PTMEG was changed from molar ratio 99 : 1 to 90 : 10 %. The resultant TPEs were systematically characterized by using various spectroscopic, thermal and mechanical analyses. Among the HBP employed, the HBP with a molar ratio 5 % gave the best result and the value of tensile strength is increased 45 % as the effect compared with without HBP. The increase of the mechanical properties of TPEs was related with the multifunctionality of HBP. Thus, the cross linked TPEs were obtained by increasing the relative amount of HBPs, since the HBP contain large number of hydroxyl group. All of these results demonstrated that small amount of HBP was one of the simple and efficient ways to modulate the properties in an affirmative way.