Field experiments were carried out to investigate effects of combined application of organic manure and inorganic fert ilizer on chemical and biological characterist ics of the degraded soil and soil fertility restoration in Central Tibet.The results showed that changes in chemical or biological characteristics of the degraded soil were quite similar among different treatments,i.e.a declining trend for organic matter,total N and total P in the plough layer,but total K and available K in different depths of the soil profile dropped significantly in the non-fert ilization treatment.Processes of soil fertility restoration were not affected in the organic manure treatment.Combined application of organic manure and inorganic fertilizer had a significant and prompt effect on harmonizing the soil environment,promoting the process of bacteria-dominated propagation of soil microorganism,enhancing the accumulation of soil organic matter and improving the structure of humic compounds,and increasing the pool of N,P and CEC,exchangeable bases as compared with the treatment of non-fertilization.Although K was applied to the soil,K deficiency was still quite obvious in all treatments.The annual changes in soil total N,available P and available K were correlated with the annual balance of N,P and K to a varying extent,and the changes in soil nutrient contents coincided with that in nutrient balance.On the basis of continuous application of organic manure,application of an increased rate of nitrogenous fertilizer,an appropriate rate of phosphates fertilizer and a high rate of potassium fertilizer had an important promoting effect on fertility restoration of the degraded soil.