The concept of interface phase was proposed in this paper with emphasis on its potential applications based on the separation of interface phase and the bulk phase. A method for determination of the volume of interface phase and the distribution of solute between bulk phase and interface phase was established . The distribution ratio of Cu(Ⅱ) was measured under different operation conditions with glucose as tracer
which could be up to 103. It is shown by the results presented in this paper that the process based on interface phase separation may have a high potential of application in the fields of chemical and biochemical engineering.