应用修正的Widom试验粒子方法在三维立方格子中计算了链节数分别为r=1,2,4,8的链状分子在不同温度、密度下的剩余化学位,然后运用热力学关系计算了以上系统在不同温度、密度下的化学位、压力和压缩因子,并求得系统的相平衡曲线和临界点。模拟结果与Flory-Huggins理论、Freed的格子场理论及胡英等工作的结果进行了比较。发现Freed理论和胡英等的工作都能较好地描述链状分子系统的相平衡行为。 The modified Widom experimental particle method was used to calculate the residual chemical order of chain molecules with chain numbers r = 1, 2, 4, and 8 respectively at different temperatures and densities in a three-dimensional cubic lattice. The thermodynamic relationship was used to calculate the above System in different temperature, density of the chemical position, pressure and compression factor, and obtain the system phase equilibrium curve and the critical point. The simulation results are compared with those of Flory-Huggins theory, Freed lattice field theory and Hu Ying et al. It is found that the work of Freed theory and Hu Ying can well describe the phase equilibrium behavior of chain molecular systems.