Tianzuo hydrothermal field (THF) in the eastern Southwest Indian Ridge (SWIR) is reported as an inactive ultramafic-hosted system and fragments of massive and altered sulphides were recovered from the hydrothermal field at (27°57′S, 63°32' E). The sulphide formation happened in the THF in two phases, at both high-temperature and low to medium temperature environment. The mineral assemblages in massive sulphides suggest the contribution of high-temperature hydrothermal fluid in the ore formation process. The presence of covellite and Fe-oxy-hydroxides in the altered sulphides indicates a low to medium-temperature environment and subseafloor alteration of fluid by seawater mixing. Elevated ΣREE contents with no significant Eu anomaly in both massive and altered sulphides further supports the subseafloor hydrothermal fluid mixed with seawater. Elevated Pd and Rh concentrations, along with their positive correlation with Cu, suggest Pd and Rh fractionation during the seawater-hydrothermal fluid mixing. 230Th/U dating results of massive hydrothermal sulphide samples give the age of 24 kyr (±2.4) and 15.6 kyr (±0.8), and an incomplete sampling demonstrates a possible minimum age of the vent field.