Abstract: A detailed process mineralogy study of a gold concentrate was carried out. Based on that， a biological oxidation-cyanidation leaching test was carried out for verification， investigating the gold loss state. The results show that the gold concentrate has a gold grade of 38.71 g/t and contains sulfur 19.69 % and arsenic 22.01 %， belonging to high-arsenic and high-sulfur gold concentrate. The gold minerals， in terms of embedding state， are dominated by encased gold with very fine grains， the dominant micro granular gold accounting for 99.53 %. The biological oxidation-cyanidation leaching process obtains a gold leaching rate of 84.04 %； the gold lost in leaching residue is mostly lost in arsenate mixtures， except for gangue minerals wrapping， and a little is lost in metallic sulfide； target minerals have good leaching performance and the gold loss characteristics are consistent with process mineralogy study results.