The temperature dependence of electrical resistivity of (Bi–Sb20) 1−x –Sn x alloys, along with liquid Bi–Sb20% alloy, have been investigated using the D.C. four-probe technique. Obvious reversible changes are observed on resistivity–temperature curves of the investigated (Bi–Sb20) 1−x –Sn x alloys, and there are clear turning points both on heating and cooling process in several experimental cycles. In case of Bi–Sb20% alloy, however, no reversible changes are observed on resistivity–temperature curves. Since resistivity is one of the physical properties sensitive to structures, it is suggested that there are reversible temperature-induced liquid–liquid transition in (Bi–Sb20) 1−x –Sn x alloys and the Sn plays an important role on the liquid–liquid transition.