Abstract: Ore from a mine in Gansu Province is a typical low-grade, arsenic-bearing refractory gold ore with an average gold grade of approximately 1.5 g/t. To improve the flotation performance of this gold ore, a process survey was conducted on the grinding-flotation circuit of the concentrator. The results of the analysis show that the recoveries of the +74 μm coarse fraction and the −5 μm ultrafine fraction are only 62.67 % and 73.42 %, respectively, and that these low recoveries are the main causes of metal loss to the tailings. Therefore, based on selective grinding and the synergistic optimization of grinding and flotation, an optimization scheme involving "coarser grinding of fineness of floating + use of a strong collector + intensified middlings regrinding" was proposed. Industrial trials were carried out following bench-scale tests. The results show that the −74 µm content in the overflow decreases from 88.8 % to 82.2 %, reducing the content of the −5 µm fraction that is detrimental to recovery. The loss rate of this fraction decreases from 6.23 % to 3.59 %. The operating parameters of the IsaMill were optimized. As a result, the middlings regrinding effect is enhanced, and the sulfide content in the newly generated readily floatable size fraction increases from 2.74 % to 11.04 %. Furthermore, butyl xanthate in the combined collector system was replaced with amyl xanthate, and the dosage ratio of amyl xanthate to MC was increased to 3∶1. The recovery of the +74 µm coarse fraction increases from 62.67 % to 73.67 %. Through coordinated adjustment of the grinding regime and the flotation reagent regime, gold recoveries in both coarse and fine size fractions are improved simultaneously, and the overall gold recovery increases from 86.26 % to 87.12 %, an increase of 0.86 percentage points, thus achieving effective linkage between grinding products and flotation performance.