用半经验势函数计算了聚四亚甲氧醚 (polytetramethyleneoxide)链在三级相互作用下的构象能 ,并用基于旋转异构态近似模型的三级相互作用近似的统计权重矩阵方法计算了该链的特征比、偶极矩比等构象性质 .结果表明 ,当考虑了三级相互作用时 ,计算结果和实验值符合得比较好 ,与由二级相互作用近似得到的结果相比 ,有很大程度的改善 The conformational energy of polytetramethyleneoxide chain under three-level interaction was calculated by semi-empirical potential function. The chain was calculated by the method of statistical weight matrix based on the approximation of the three-level interaction of the rotational isomerism model , Dipole moment ratio and other conformational properties.The results show that when considering the three-level interaction, the calculated results are in good agreement with the experimental values, which are very large compared with the results obtained by the approximation of the second-order interaction Improve the degree