Abstract: A runoff yield calculation method and device based on double free reservoirs, and a storage medium are provided, the method includes: forming a four-layer vadose zone structure by making a tension water storage layer be located under a deep vadose zone based on a three-layer vadose zone structure of a Xin'anjiang model; dividing a space occupied by free water in the four-layer vadose zone structure into an upper free reservoir and a lower free reservoir; calculating a time interval runoff yield by using a saturation excess runoff method; and dividing, based on a runoff yield structure of the double free reservoirs, the time interval runoff yield into a surface runoff, an interflow and a subsurface runoff. The method proposes a runoff yield structure of double free reservoirs, which can be well applied to semi-arid and semi humid watersheds with deeper buried depth of shallow groundwater.