Nitrogen (N-2) fixation is a challenging and vital issue in chemistry. Inspired by the fact that the active sites of nitrogenases are polynuclear metal sulfide clusters, the reactivity of gas-phase metal sulfide clusters toward N-2 has received considerable attention to gain fundamental insights into nitrogen fixation. Herein, neutral tantalum sulfide clusters have been prepared and their reactivity toward N-2 has been investigated by mass spectrometry in conjunction with density functional theory (DFT) calculations. The experimental results showed that Ta3Sn (n = 0-3) could adsorb N-2, while Ta3S4 was inert to N-2. The DFT calculations revealed that the complete cleavage of the N N bond on the trinuclear metal center in the Ta3S0-3/N-2 reaction systems was overall barrierless under thermal collision conditions. The sulfur ligands can facilitate the approaching of N-2 toward the metal center but weaken the electron-donating ability of the metal center. The inertness of Ta3S4 is ascribed to the electron-deficient state of Ta-3 in Ta3S4 and the least effective orbital interaction in the Ta3S4/N-2 couple. This study provides new insights into the ligand effect on the interaction of the metal clusters with N-2.