Abstract: To explore the characteristics of the effect of ore particle size on the capillary flow of solution in an ore heap, solution capillary rise experiments of two groups of ore particles, mono-size and non-uniform, were performed with an established capillary rise experimental device. The relationship of solution capillary rise height with time and the corresponding fitting equations were obtained. The regularity of solution rise velocity with time was analyzed. It is found that at the beginning of the experiment, the ore heap solution rises quickly; with the increase of time, the solution rise velocity decreases and eventually drops to zero; the maximum solution rise height and velocity have negative correlation with ore particle size. Immobile solution content inside the ore heap formed by capillary action increases with the decreasing of average particle size, and a wide range area of immobile solution will form when the content of fine particles in the ore heap is too much, which can influence the solution seepage of the ore heap.