Aim: Peatlands are the most important global soil carbon reservoirs due to low decomposition rates. However, research on how the quality and geographic environment of peatland plant litter influence its decomposition remains limited. This article aims to explore the influence of geographical origin and plant groups on the initial chemical characteristics and decomposition processes of peatland litter. Location: Plant materials were collected from three peatlands in East China along a latitudinal gradient: Dajiuhu, Hani, and Mangui peatland. The experiment was conducted in Hani peatland. Time period: The three - year decomposition experiment started in early October 2014. Major taxa studied: Common species including mosses ( Sphagnum), graminoids ( Carex) and shrubs ( Betula) from the three peatlands. A total of nine plant species were included. Methods: In China, plant materials were collected from three peatlands across different temperature zones along a latitudinal gradient to conduct a three-year litter decomposition experiment using litter bags in Hani peatland, Changbai Mountains. Results: 1. The initial chemical quality and decomposability of plant litter varied by plant functional group and geographic origin. 2. Decomposition rates of plant litter, in descending order, were: graminoids ( Carex) > shrubs (Betula) > mosses (Sphagnum). 3. Plant litter from the northernmost peatland (Mangui) exhibited the lowest decomposition rate. However, the response of leaf litter decomposability to geographic origin differed among functional groups. 4. Lignin and total phenols were found to inhibit the decomposition of plant litter. Main conclusions: Geographic environment and plant functional group type have crucial effect on the decomposability of peatland plant litter by shaping biochemical traits of the plants. Current and future climate warming may alter the decomposability of litter and microbial activity, likely diminishing carbon accumulation function of peatlands.