Abstract: In this work, poly(hexamethylene terephthalate)(PHT), poly(hexamethylene 2,6-naphthalate)(PHN), and poly(hexamethylene terephthalate-co-hexamethylene 2,6-naphthalate)(P(HT-co-HN)) were prepared using Ti(OBu)4 and Sb(OAc)3 catalysts. Crystallization behavior, crystallization kinetics, and crystal structure of PHT, PHN, and P(HT-co-HN) were analyzed using differential scanning calorimetry (DSC) and wide angle x-ray diffraction (WAXD). DSC non-isothermal cooling curves show that PHT, PHN, and P(HT-co-HN) are all crystallizable. The crystallization peak temperature of PHT, PHN, and P(HT-co-HN) prepared from the dual catalyst (Ti:Sb = 1:1) is higher than that of the corresponding polymer prepared from Ti catalyst. Analysis of the modify avrami equation shows that the half-life (t1/2) of crystallization of the P(HT-co-HN) prepared from the Sb catalyst has the shortest half-life (t1/2) of crystallization, followed by the duel catalyst and the Ti catalyst. The Kissinger method was used to calculate the activation energy of samples prepared from Sb, Ti, and dual catalyst. In PHT and PHN, the activation energy of both PHT and PNH prepared from dual catalyst is less than that of the corresponding polymer prepared from Ti catalyst. The activation energy of Sb catalyst in P(HT-co-HN) prepared from Sb catalyst is the smallest. In Ti catalyst and dual catalyst, the activation energy is P(HT-co-HN) > PHT > PHN. The crystallization rate is PHN > PHT > P(HT-co-HN). Sb catalyst can increase the crystallization rate of PHT, PHN, and P(HT-co-HN). Through WAXD analysis, all crystal diffraction peaks of P(HT-co-HN) were found to be related to PHT and PHN. In P(HT-co-HN), the related diffraction peaks of the related crystals of PHT and PHN have a wide lattice d spacing, indicating that co-crystallization had occurred. The crystallinity of PHN in P(HT-co-HN) is higher than that of PHT, indicating that the PHN in P(HT-co-HN) is easier to crystallize than PHT.