Litter-derived metabolites play important ecological roles in plant-soil systems. In this study, the litters of 5 typical arboreal, shrubby and herbaceous species, including Robinia pseudoacacia, Pinus tabuliformis, Hippophae rhamnoides, Setaria viridis and Lespedeza daurica, in the hilly and gully region of the Loess Hilly Region were studied. Soil from a site that far from the litter sampling area was mixed with sterile water, fully shocked and precipitated, and the supernatant was used for inoculating litters. Then, based on an indoor-decomposition simulation under room temperature (25 ℃) and constant humidity (the water-holding rate of litters was approximately 100%), and the degradation or release characteristics of 7 types of metabolite in this process were studied, aiming to get more deeply understand the decomposition process of litters and its subsequent ecological effects, and to provide scientific basis for the management of forest and grass ecosystems. The results indicated that: (1) during the decomposition process of 150 d, the lignin of 5 types of litter showed little degradation (<30%) in the early stage (0-60 d) and tended to stagnate in later stage; most (>80%) of water soluble phenolics, condensed tannins and flavones released rapidly in the early stage (0-30 d) of decomposition, but slowed down significantly in later stage. The release of terpenoids was continuous and even accelerated at the later stage during the experiment. The release of soluble sugars and amino acids showed a trend of rapid release in a short time and then slow release. In general, except for lignin, which degraded significantly slower during litter decomposition, all other metabolites exhibited an overspeed release trend. (2) The annual degradation or release rates of 7 types of metabolite were significantly higher in the litters of H. rhamnoides and R. pseudoacacia than in the those of L. daurica, S. viridis and P. tabuliformis (P<0.05). (3) The annual degradation or release rates of lignin, condensed tannins, terpenoids and flavones were not significantly correlated with their initial contents (P>0.05), while the annual release rates of water soluble phenolics, soluble sugars and amino acids were positively correlated with their initial contents (P<0.05). In conclusion, except for lignin, which degraded significantly slower during litter decomposition, all other metabolites exhibited an overspeed release trend; the annual degradation or release rates of almost all these 7 types of metabolite were positively correlated with the initial nitrogen and phosphorus contents of litter.