The Changpo—Tongkeng Tin—Polymetallic Deposits is located on the west deposits belt of Dachang Tin—Polymetallic Orefield in Guangxi Province. The layered orebodies have a wide spread. However, there are some major debates on their origin due to the lack of direct studies on their metalogenic ages. Data from U-Pb LA-MC-ICP-MS analysis of three cassiterites from layered Orebody #92 show that the n(238U)/n(207Pb) — n(206Pb)/n(207Pb) isochronage of 95.8±2.6 Ma (MSWD = 6.3), is consistent with the dating results of quartz 40Ar/39Ar, sanidine in-situ 40Ar/39Ar, and quartz Rb-Sr (91.4 ± 2.9 ～ 94.52 ± 0.33 Ma). This indicates that the in-situ U-Pb LA-MC-ICP-MS analysis of cassiterites is plausible and effective. We chronological approach, it is suggested that the ore-forming of this ore body is coeval with second intrusion of Longxianggai Terrace (96.6 ～ 93.86 Ma), and that the genesis of the deposit is closely associated with magmatism.