In this paper, we calculate partition function, entropy and free energy of polyoxyethylene diethyl ethers chains by using Rotational Isometric State model, and calculate the excluded volume effect with Monte Carlo simulation. 本文采用旋转异构态模型计算了无扰polyoxyethyleneDiethylEthers(POEE)链体系的配分函数、熵和自由能,同时采用MonteCarlo方法计算了POEE链在良溶液的排斥体积效应。