采用胆甾相液晶的格胞理论，运用一定的统计方法，导出分布函数，定义序参数张量，由此推导出自由能表达式．在定域坐标系中，对胆甾相的长程取向序参数Ｓ和相诱导双轴序参数Δ进行了数值计算．所得的结果较前人有了不同程度的改善，和实验接近 Using the lattice theory of cholesteric liquid crystal, we derive the free energy expression by using some statistical methods, deriving the distribution function and defining the order parameter tensor. In the local coordinate system, the long-range orientation order parameter S and the phase-induced biaxial order parameter Δ of the cholesteric phase are numerically calculated. The results obtained have improved to some extent from the previous ones and are close to the experiment