The tin ore belt of southeast Yunnan is a tectonicmagmatic-tin metallization belt formed in the Yanshan tectonic cycle. The tin belt as a unique system trends in NWW direction and acrosses a number of tectonic elements.The formation of tin ore deposit was characterized by the succession of polyphase mineralization and the enrichment was reached by the compounding and superposing metallogensis in Late Yanshanian. In later metallogeni period the tin ore formation was characterized by cassiterite-sulfide type. In space, the tin-polymetal metallized area is consistent with folding-uplift structure, geophysical and geochemical anomalies and the ring image shown by remote-sensing.A metallogenic model is suggested to indicate the multisource and the processes of mobilization, transpotation, precipitation and oreformation. In this model, it is also suggested that the intrusion of the granite is a main control in the ore-formation.