Abstarct: In this research, alkaline oxidation pretreatment of Zarshuran refectory gold ore and its influence on the performance of cyanidation process was investigated. Taguchi method-orthogonal array design was applied to evaluate and optimize the influence of five main factors including solution pH, aeration rate, agitation speed, temperature and oxidation time. A linear regression model with R2 of 0.9706 was fitted to experimental data for relationship between the gold dissolution rate and influential factors. The results indicated that the agitation speed didn’t have significant impact on the gold recovery in the range studied, while oxidation time and temperature were the most significant factors. Au recovery increased with increasing the aeration rate, pretreatment time and temperature and decreasing the solution pH. Using Taguchi orthogonal array optimization technique, the maximum gold recovery was obtained to be ~96.72%. The optimal condition was also found to be 11 for solution pH, 150 mL/min for aeration rate, 240 rpm for agitation rate, 50 °C for temperature and 24 hours for oxidation time.