Abstract: Through continuous sampling, the physical and chemical properties of pig litter in the microbial fermentation bed were analyzed, and results showed that the physico-chemical properties were changed significantly in the different litter.The water absorption of the litter used for 5-16months decreased with the passage of time, but pH, moisture content, conductivity, salinity, organic matter and total nitrogen, phosphorus and potassium increased significantly.Organic matter content of the litter used for 5, 7, 9and 16 months were 59.72%、 49.34%、44.94%and 38.41% (P<0.05) , respectively.It reduced gradually with the passage of time and the difference was significant.Total nitrogen contents reduced with the gradual reduction of litter fermentation, but total phosphorus, potassium content were on the rise by using stretch the time.