Mountains are hotspots for biodiversity research because they harbor high number of species and cover a wide range of abiotic factors along altitudes. Compared with above-ground plants and animals, soil animal communities along altitudinal gradients have been little studied. Collembola are among the most abundant soil invertebrates contributing to essential ecosystem functions such as decomposition processes. We used Collembola as model soil animals and analyzed changes in their community structure in litter and soil of forests along a gradient ranging from 800 to 1700 m at the Changbai Mountain. Further, changes in four taxonomic diversity indexes (richness index, evenness index, Shannon-Wiener index, and Simpson diversity index) and four functional diversity indexes (functional richness index, functional evenness index, Rao's quadratic index, and functional divergence index) were studied. A total of 5,542 Collembola individuals, belonging to 12 families, 42 genera, and 83 species were sampled, with Isotomidae being most dominant (>50% of total individuals). Non-metric multidimensional scaling showed that Collembola community composition varied in both litter and soil. Species of Entomobryidae, Tomoceridae, and Neanuridae mostly colonized the litter layer, whereas Onychiuridae mostly colonized the soil. We used linear and quadratic regression models to explore altitudinal patterns in Collembola diversity. In litter, the richness, Shannon-Wiener diversity index and Simpson diversity index significantly positively correlated with altitude. By contrast, in soil, the taxonomic diversity indexes did not change significantly with altitude. For functional diversity, in litter functional richness index and Rao's quadratic index followed a hump-shaped pattern along the altitudinal gradient. In soil the functional richness index also showed the same trend, but other functional diversity indexes did not change in a consistent way with altitude. Overall, the results highlight that it is crucial to consider the vertical distribution of soil animals in litter and soil, and use multiple dimensions including taxonomic and functional diversity measures for understanding changes in diversity patterns of soil fauna along altitudinal gradients.