Abstract: Based on zone melting theory and solute mass transferring character between water and ice phases during water sample freezing process, it is illustrated that zone melting is a consecutive extraction process, and distribution coefficient and frozen fraction factor are main parameters affecting enrichment efficiency. Using chrysanthemum extract as model sample, the enrichment efficiency is determined by analyzing frozen fraction factors under different frozen time and solute contents before and after frozen by high performance liquid chromatography. It is found that the experimental data agree well with the theory values, the accuracies are all above 93%. For components with low distribution coefficients, over 50 folds enrichment efficiencies are achieved.