Abstract: The present paper relates to the study on the extraction of tin and zinc from hydrochloric acid solution by TBP. It is discovered that if kerosene is selected as the diluent for TBP, then third phase will appear. When MIBK is used as modifier and concentration of hydrochloric acid is bigger than 7.2 mol/L, the third phase will appear. It is due to the missibility of MIBK in concentrated acid solution.The optimum extraction conditions for the separation of tin and zinc are as follows: 25%TBP-10%MIBK(or 1-decanol)-65% kerosene, 6 mol/L HCl and room temperature. Scrubbing can remove zinc in the loaded solvent containing the both metals in the extraction stage. If 6 mol/L HCl is used as scrubbing agent, the completeness of scrubbing of zinc reaches about 95%. Dilute acid solution (0.24 mol/L HCl) is adopted as stripping agent of Sn~(4+) from the loaded solvent.Extraction ability of Sn~(4+) and Sn~(2+) by TBP is compared experimentally, and Sn~(4+) appears a little better ability than Sn~(2+). D_(Zn)(2+) decreases with increasing the initial concentration of Sn~(4+), but when Sn~(4+) is less than 18 g/L, D_(Zn)~(2+) does not change.