The decomposition rate of litter and its temperature sensitivity Q₁₀ could affect the return of organic carbon to the soil, and in turn, its response to global warming. However, exactly how the quality of organic carbon affects litter decomposition and its temperature sensitivity is still relatively unknown. In this study, field and laboratory incubation experiments were conducted to investigate how the quality of organic carbon affects litter decomposition and its temperature sensitivity. The leaf litter of reed (Phragmites australi) was collected in the Yellow River Delta, China, and the quality of organic carbon was assessed through solid-state ¹³C nuclear magnetic resonance spectroscopy (¹³C NMR). The results showed that (1) the relative abundance of O-alkyl and di-O-alkyl C was reduced, and the relative abundance of aromatic C was increased following litter decomposition. The ratios of hydrophobic to hydrophilic C and aromatic to O-alkyl C were also increased at the last stage of litter decomposition. These results indicate that the stability of organic carbon was enhanced during litter decomposition. The respiration and mass loss rate of litter also decreased during litter decomposition, and (2) the mass loss of litter was mainly controlled by the relative abundance of alkyl and O-alkyl C and C/N, whereas the cumulative CO₂ production of litter was mainly controlled by the relative abundance of O-alkyl and di-O-alkyl C. Furthermore, the Q₁₀ value of CO₂ production was affected by the relative abundance of carboxyl C. In general, the relative abundance of alkyl, O-alkyl, di-O-alkyl, and carboxyl C are more effective in predicting litter decomposition and its temperature sensitivity compared to litter stoichiometry.