Abstract: A gold ore in Zhashui，Shaanxi Province belongs to carbonaceous argillaceous siltstone type and barenci-cataclastic type gold ores.The gold in the ore mainly exists in the form of submicroscopic gold，and the main carrier minerals are pyrite and arsenopyrite. In order to determine the development and utilization technology of the ore，beneficiation test was carried out. The results showed that under the condition of grinding fineness of -0.074 mm accounting for 78%，a gold concentrate with gold grade of 108.15 g/t， silver grade of 27.00 g/t and arsenic content of 10.78%，and gold recovery rate of 92.14% can be obtained by the process of two roughing，one scavenging and middling return. The test indexes is better and can be used as the design basis for the concentrator.

Key words: submicroscopic gold, pyrite, arsenopyrite, flotation