To raise reliability and accuracy of laboratory experiments on unsaturated coal gangue leaching, the rainfall simulation system of traditional unsaturated coal gangue leaching instrument was improved. Thus, the simulation of random rainfall path was achieved, and the volume of coal gangue that can be leached effectively increased accordingly. Meanwhile, the coal gangue in Sangshuping coal mine, Hancheng City, were selected as study objects, and the characteristics of coal gangue leaching under various rainfall intensity conditions and weathering degree conditions were revealed. The results showed that: (1) The values of electrical conductivity (EC) and SO_4^2-concentration (c) of leachate decreased with time. And the process can be divided into quickly falling stage and slowly falling-stabilizing stage. (2) Exponential functions, Fourier functions and power functions were employed to fit the relation curves of EC-t and c-t under different experimental conditions, and the R2 values of fitting functions were 0.87~1.00. (3) With the rainfall intensity of 167mm/h, the values of EC and c of leachate had the highest sensitivity index to weathering degree, namely 3.14 and 7.64. (4) Compared with the other conditions, the combine condition of rainfall intensity of 83mm/h and coal gangue with triennial weathering could produce higher values of EC and c of leachate. Finally, three conclusions were obtained, including: (1) The extraction quantity of coal gangue elements, which tended to be stable in 3~5 hours after the start of experiment, mainly decreased as the exponential function form. (2) Weathering degree was the main control factor that affected the extraction quantity of coal gangue elements. (3) A smaller rainfall intensity or a higher weathering degree was beneficial to consistent extraction of coal gangue elements.