The conformational analysis of polyoxanorbornene (PONB) chain is investigated with the AM1, MM2, AMBER and OPLS methods taking into consideration the possibility of binding of oxanorbornene monomers to each other at various positions. i.e. exo-exo, exo-endo, endo-endo. The chain that is formed by connecting exo-endo positions of them monomers has lower torsional barrier energy than those formed with bonds at other positions and has more flexibility. It is determined that thredisyndiotactic chain formed by exo-endo addition has coil shape. Disyndiotactic chain formed by connecting oxanorbornene monomers in mixed type has a linear Structure. It is found that the repeat unit conformations of thredisyndiotactic and disyndiotactic chains of PONB are TGTG(-) and (TGTG(-))(2), respectively.