<p>The Shuixie Cu–Co ore field, located in the southwest Meso-Cenozoic Lanping Basin on the southeastern margin of the Qinghai–Xizang Plateau, SW China, is a well-known Cu-polymetallic ore field with structural control features. The Alin deposit is a newly discovered gold-rich ore deposit in this ore field, containing more than 5 tons of gold with an average grade of 4.02&#xa0;g/t. Previous studies have suggested the occurrence and enrichment mechanisms of gold. However, the ore genesis remains unclear. In this paper, we further investigate the microtextures and trace element and sulfur isotopic compositions of pyrites. Four distinct pulses of pyrite and arsenopyrite in the Alin gold deposit were identified. The arsenic (As) contents range from 3% to 8% in pyrite, indicating the enhanced incorporation of Au⁺ into the pyrite lattice. Co, Ni, and Cu are likely present in pyrites from Pulse 1 to Pulse 2 in solid-solution form, whereas sharp peaks of Au, Co, and Cu contents suggest that mineral inclusions were captured within pyrites from Pulse 3 to Pulse 4. The temperature of the ore-forming fluids gradually decreased and then increased during Pulses 1–4. The <i>δ</i>³⁴S values of pyrite from Pulses 1–4 range from&#xa0;−&#xa0;1.22‰ to&#xa0;+&#xa0;6.48‰, indicating possible magmatic hydrothermal sulfur influx during ore mineralization. Pyrites in the Alin Au deposit may have been influenced by deep magmatic processes, displaying the typical features of Carlin-type gold deposits.</p>