Ultrafine milling technology is used to treat gold-bearing sulphides and to investigate the effects of minerals size, milling time, liquid/solid ratio, NaCN consumption and leaching aid on leaching rate of gold. The results indicate that shorter treating time, decrease of NaCN consumption of 60% and increase of gold leaching rate of 15% can be obtained by the ultrafine milling technology compared with traditional cyanide leaching. Potential exists for the new process to form the basis for an economically viable, high-efficiency process for treatment of gold-bearing sulphides.