Abstract:This paper first presents LA-ICP-MS titanite in situ U-Pb dating results for the the Neoproterozoic granites in the Erguna Massif with the aim of constraining their forming times, in order to provide new evidence for determining the Neoproterozoic magmatic events, and discusse its geological significance. Titanite grains from two representative samples of Mangui and Moerdaoga plutons are euhedral-subhedral diamond in shape, and not display specific almond hole of metamorphic titanite in microphotographs, implying a magmatic origin. Titanite U-Pb dating results demonstrate that the analyses, each of two plutons, plot along a fine discordia line with lower intercept ages of 873 ± 22 Ma and 783 ± 31 Ma, which correspond to 206Pb/238U weighted mean ages of 872 ± 18 Ma and 789 ± 17 Ma, respectively. Combined with the published data, it is concluded that Mangui pluton, the original earliest product of the Neoproterozoic magmatism in the Erguna Massif, actually formed at ~850 Ma, not 957~927 Ma as previously believed, whereas Moerdaoga pluton actually formed at ~790 Ma, rather than ~762 Ma as was previously suggested. At present, the modified and previously published ages demonstrate that the Neoproterozoic magmatisms in the Erguna Massif can be subdivided into five stages: 915~905 Ma, ~847 Ma, 818~808 Ma, ~792 Ma and ~738 Ma.