The phase transition curves of a multi-component TN liquid crystal mixture (TN 88-1) and a multi-component cholesteric liquid crystal mixture (Ch 88-2) were plotted by using a differential scanning calorimeter. The phase transition temperature and phase transition heat were obtained from the DSC curves. The results show that the components of TN 88-1 are compatible and they can form a stable mixture with CB 15 chiral liquid crystal. The components of Ch 88-2 are not compatible and Poly (MMA-BMA) can greatly improve their compatibility.