Abstract: The coal gangue of northern Shaanxi is set as the research object, a self-developed leaching instrument was used to simulate rainfall conditions, leaching experiments were attempted under different rainfall intensity and different grain size of gangue. The results are as follow:the leachate conductivity shows three stages, that is fast decline, slow decline and stable fluctuation with test time, the Cr concentration shows two stages:fast decline and slow decline (or stable fluctuation) with test time; With the increase of rainfall intensity by 68%, the mean conductivity in large and small particle size groups are decreased by 18.9%, 24.6%, the Cr mean concentration are decreased by 18.8% and 22.0%; With the increase of mean particle size by 50%, the mean conductivity in large and small rainfall intensity groups are decreased by 4.0% and 10.7%, the Cr mean concentration are increased by 34.5% and 29.2%. The conclusions are:the release of soluble elements in gangue shows a law of exponential decay, rainfall intensity is more sensitive to the release of soluble elements; Cr leaching process is similar to other soluble substances which follows the law that concentration decreases in several stages and stabilizes gradually, particle size is more sensitive to the release of Cr; Cr leaching concentration peak appears earlier in weathered surface than fresh surface, which makes concentration fluctuation in later stage of leaching; The overall release level of soluble element depends on the total sample surface area, but Cr mainly releases through weathered surface of gangue.