Abstract: In order to improve the sulphuric acid leaching rate of Yulong oxide copper ore orthogonal experimental design is applied to optimize the parameters of the acid leaching process, which can increase the copper leaching efficiency and provide the theory basis for industrialized production. Single factor optimum interval of oxide copper ore sulphuric acid leaching is firstly analyzed and then orthogonal optimization are conducted with factors of temperature, initial acidity, leaching time, liquid-solid ratio and grinding fineness being considered. It is shown that the temperature, initial acidity, leaching time, liquid-solid ratio and grinding fineness have contributions to the copper leaching efficiency, and temperature has greatest effects on the leaching rate. When the temperature is 30 ℃, the initial acidity is 100 g/L, the leaching time is 2 h, the liquid-solid ratio is 2:1 and grinding fineness of the particle size≤74 μm with mineral powder accounting for 65 %, copper leaching efficiency can be as high as 79.45 %.