The “home-field advantage” for decomposition, a specific plant-soil interaction, suggests that leaf litter of a given species decomposes faster on soils under the conspecific species (i.e., the “home” field), with its own soil properties, than in soils under different species (i.e., “away”). This home-field advantage of leaf litter decomposition has been often observed in many previous studies, but the underlying mechanisms remain unclear. We conducted a reciprocal litter-decomposition experiment in the Hakkoda Mountains, Aomori, using two species with different leaf traits: evergreen coniferous tree, Abies mariesii and deciduous broad-leaved tree, Fagus crenata. These species shift their dominance along an elevation gradient, with a transition zone where both species coexist. In the transition zone, we explored the home-field advantage of decomposition and its controlling factors. We found that the leaf litter decomposition rate of each species was generally faster in their “home” than in “away”, and the magnitude of home-field advantage was intricately governed by temperature, soil properties (e.g., soil pH, soil C), which are influenced by forest species composition, and leaf litter traits (e.g., nitrogen), along the elevation gradient. We further suggest that such specific plant-soil interaction may change the impact of temperature on leaf litter decomposition.