Hydrothermal activity on mid‐ocean ridges plays an important role in shaping marine chemistry, yet the variability of hydrothermal venting and its forcing mechanism remain elusive. Here, we analyzed a sediment core obtained near the tectonic‐controlled Tianxiu vent field, Carlsberg Ridge, to reconstruct the hydrothermal venting history. The core documented two significant hydrothermal events (H1 and H2) in the past 30 ka. H1 occurred at 24.1–24.5 ka during the Last Glacial Maximum (LGM), while H2 occurred at 10.5–11.6 ka during the deglacial period. Compared to H2, H1 was relatively weak, and it occurred concurrently with a tectonic event. We suggest that H2 was caused by the increased melt production associated with the decompression melting of the upper mantle during sea‐level fall, which is consistent with previously published records, whereas H1 was likely triggered by an intense tectonic event associated with depressurization during the LGM, which was previously unrecognized. Plain Language Summary Hydrothermal systems are controlled not only by magmatism but also by tectonism. Previous studies have shown that there is a relationship between the variability of hydrothermal activity and sea‐level changes. Increased melt production during glacial periods has been invoked to explain the enhanced hydrothermal activities during glacial terminations. However, little attention has been paid to the relationship between hydrothermal activity and tectonic events during the glacial–interglacial cycle. Based on the analysis of a sediment core collected near the tectonic‐controlled Tianxiu vent field, Carlsberg Ridge, we reconstructed the hydrothermal venting history and found that enhanced hydrothermal activities not only occurred at 10.5–11.6 ka during the last glacial termination but also occurred concurrently with an intense tectonic event at 24.1–24.5 ka during the Last Glacial Maximum. We infer that this earlier hydrothermal event was induced by the improved permeability of the oceanic crust due to depressurization during the glacial sea‐level fall. This is the first time that the hydrothermal venting history of a tectonic‐controlled hydrothermal system in the Indian Ocean is characterized, and the coupling between hydrothermal and tectonic events associated with sea‐level changes is revealed. Key Points A 30 ka history of hydrothermal and tectonic activity was reconstructed for the Tianxiu vent field The hydrothermal event at 24.1–24.5 ka was triggered by tectonic events resulting from depressurization during the Last Glacial Maximum The hydrothermal event at 10.5–11.6 ka was caused by increased decompression melting of the upper mantle during the Last Glacial Maximum