///Cassiterite-hematite-calcite vein-type orebody was found in Songshujiao mining area of Gejiu Tin-deposit, and was reported in this paper. Preliminary study shows that the vein-type orebody is the result of the late ore-forming fluid condensated in the transport channel. The paper also preliminary discussed the cause of its genesis. According to the comparison between the Gejiu tin-polymetallic deposits and the Red Sea-type hydrothermal deposits, we believe that there are two models for the “Interstratified oxidized ore” of the Gejiu and the Red Sea-type orebodies; one is thermal brine staged oxidize from the top down, and another is ore-forming fluid oxidized from the bottom up gradually.