Abstract: A refractory gold ore from Gansu Province has a gold grade of 1.63 g/t and a sulfur grade of 2.25 %. The gold primarily exists in the form of inclusion gold with finely disseminated particles. Based on the ore characteristics, systematic flotation tests were conducted, and coarse concentrate regrinding and types and dosage test of reagents were also performed, ultimately determining the optimal flotation parameters. The closed-loop test yields a gold concentrate grade of 18.11 g/t with a gold recovery rate of 83.44 %. Compared to the gold concentrate grade obtained from conventional on-site flotation （12 g/t）, the gold concentrate grade improves by 6.11 g/t, while the gold recovery rate remains largely consistent with on-site performance. The study indicates that regrinding the coarse concentrate helps improve the liberation degree of gold-bearing minerals, thereby enhancing the gold concentrate grade. However, since the gold minerals in this ore are mostly present as finely disseminated inclusions within sulfide minerals, even fine grinding makes it difficult to achieve effective separation between gold and sulfur, resulting in limited improvement in gold concentrate grade. This research provides a reference for the on-site production.