Based on the current knowledge of sulfide ores, an orthogonal experiment design is made to conduct experiments on the sulfide ore samples obtained from a certain mine. An orthogonal array with four factors and three levels is adopted. The importance of factors that affect the caking of sulfide ores is determined through a direct analysis on range. It is shown that different factors have diverse effects on the caking degree. The caking state of the sulfide ores can be significantly changed by changing these factors. The influences of different factors on caking are in the following order: temperature > water content > humidity > particle size. According to the trend analysis, the variation of the caking ratio against each factor is obtained. On the basis of orthogonal experiments, single factor experiments are carried out to further qualitatively analyze the relations between temperature, humidity, water content, particle size and caking ratio. Finally fitting curves of these factors versus caking ratio are obtained. The feasibility of orthogonal experiments is confirmed. Single factor experiments demonstrate that the temperature, humidity, water content, particle size are closely related with the caking of sulfide ores.