Preferential flow is common in soil with preferential channels and greatly affects soil water infiltration. Although previous studies have made great progress in clarifying preferential flow, there has been little investigation of the effect of the preferential channel on preferential flow, and it is necessary to understand how precipitation intensity affects preferential flow. In this study, to examine the preferential flow characteristics of rare-earth ions by the dyeing method and moisture sensors and to determine the influence of the development degree of the preferential channel in a rare-earth ore on the characteristics of preferential flow with different liquid injection intensities using Brilliant Blue FCF, indoor and outdoor experiments were carried out to monitor the development of preferential flow in real time and compare the development degree of soil preferential flow with different liquid injection intensities. The results show that the more developed the preferential channel, the more developed the preferential flow, and that the influence of the liquid injection intensity on the preferential flow rate and its degree of enhancement increases with increasing soil preferential channel development. However, when the injection intensity is low, preferential flow cannot be formed even in soil with abundant macropores. When studying the influence of liquid injection intensity on preferential flow, the influence of the development degree of the preferential channel is considered. The results of this study enrich the theory of preferential flow, enabling the evaluation of agricultural water use, soil pollution migration, groundwater pollution risk assessment, and clarification of landslide mechanisms.