The mathematical models are deduced for the evaluation of the growth interface shift due to the solute redistribution during the normal Bridgman process and the ACRT-B process. Hg,.,,Cd,,,Te and other II-VI quasi-binary alloys are taken as examples in the calculation. The results show that: (1) in the normal Bridgman process, the shift of the growth interface mainly takes place in the intial transient region. At the growth temperature gradient of 10 K/cm, displacement of the growth interface as large as about 80 mm occurs in this region. In the steady growth region, the interface position becomes fixed until the final transient region starts, then the interface moves downward again. Increasing the growth rate results in a sharper shift speed in the initial transient regions even though the total shift distance does not change. (2) In the ACRT-B process, the shift of the growth interface takes place continuously in the whole growth process and is independent of the growth rate.