The invention discloses a carbonaceous gold ore inhibitor and a using method thereof. The carbonaceous gold ore inhibitor aims at solving the problem that preg-robbing carbon (being mainly of organic carbon) in carbonaceous gold ores adsorbs gold cyanogen complex ions. The carbonaceous gold ore inhibitor comprises the following three materials in percent by mass: 10%-30% of sodium dodecyl benzene sulfonate, 10%-30% of sodium lauryl sulfate and 50%-70% of polyoxyethylene sorbitan laurate. The composite inhibitor is a surface active agent, reduces the adsorption loss of the gold cyanogen complex ions through the adsorption effect on preg-robbing carbon/ iron-sulfur-arsenic oxidation bacteria residue bodies and remarkably increases the cyanidation leaching rate of gold. The inhibitor has the advantages of strong adaptability, good water solubility, good dispersion effect, small influence on environments, simple operation and the like. The popularization and application of the composite inhibitor and the using method thereof can remarkably increase the cyanidation recovery rate of gold in the carbonaceous gold ores and increases the comprehensive utilization ratio of resources and the economic income of enterprises.