Peat swamp forest is a vulnerable ecosystem and hard to recover to its original condition after disturbances. The degradation of peat swamp forest can lead to the changes in vegetation structure, species composition as well as regeneration status. However, information regarding species composition at different types of peat swamp forest remains limited. This study aims to investigate the diversity of plant species at various peat depths in Kalimantan. This study used 399 plots (21 plots in Muara Siran, East Kalimantan and 18 plots in Tumbang Nusa Research Station, Central Kalimantan) with a total area of 400 m2 to measure species diversity, density, frequency, and dominance and importance value index. Result shows that there is a difference in plant species diversity between the two study sites. The number of species found in peat swamp forest in Muara Siran, East Kalimantan was 34 species, consists of 18 species of seedling, 24 species of sapling, 17 species of pole and 13 species of tree. Meanwhile, a total of 55 species was found in Tumbang Nusa Research Station, Central Kalimantan, consists of 34 species of seedling, 32 species of sapling, 27 species of pole, and 22 species of tree. This species composition difference is caused by the difference in peat depths. Shallower peat depth (<5 m; Central Kalimantan) tends to have higher species diversity than deeper peat depth (>5 m; East Kalimantan). The major species found in Muara Siran, East Kalimantan are Combretocarpus rotundatus, Shorea parvifolia, Shorea balangeran, and Eugenia sp.. Meanwhile, major species found in Tumbang Nusa Research Station, Central Kalimantan are Combretocarpus rotundatus, Cratoxylon arborescens, Dactylocladus stenotachys, dan Shorea teysmaniana. These results give some hints that natural regeneration in peat swamp forests should consider the typology of peat lands as well as species composition in natural habitat. Keywords: peatland, diversity, typology, peat depth