Abstract: This is a paper in the field of process mineralogy. Daqiao gold mine is a super-large gold mine discovered in the Qinling region,but in the process of mining primary ore, it is found that the recovery rate of gold is very low by using the traditional beneficiation process, so the refractory pre-deposit is determined, this paper aims to investigate the occurrence state and refractory factors of gold in the deposit. Through microscopic identification, SEM, EPMA, and chemical analysis, combined with mineral processing tests, it is found that gold mainly exists in siliceous breccia in the form of natural gold and silver gold. The granularity of gold and gold-bearing minerals is very small, so that in the process of beneficiation,the sandal can not be dissociated to a high degree under the condition of very fine grinding granularity, which is the main reason that restricts the beneficiability of the ore deposit, it is also found that the ore contains more carbon, which is another reason restricting the ore beneficiability.