The invention discloses a method for measuring interflow in forest soil, and belongs to the field of forest soil ecological study. The method is characterized in that the system utilizes the soil profile and consists of an interflow flow collecting groove, a flow guide pipe and an interflow collector, wherein the flow collecting groove is embedded into a soil body in different layers of the soil profile, the interflow is collected, and the interflow is guided into the collector for completing the collection of the interflow. The method has the advantages that the structure is compact, the system is reasonable, the method is simple, the realization is easy, a scientific and reasonable small-dimension measuring system is provided for the study of the forest soil hydrology process, the moisture and nutrient balance and moving and the like, and greater popularization and application values are realized in the fields of forest soil ecology, forest hydrology, water and soil conservation and the like.