Livestock wastewater and agricultural straw are the two main sources of agricultural nonpoint source pollution, then how to deal with these wastes is becoming more and more important.Anaerobic digestion is an attractive technique for bio-wastes treatment, which can convert bio-wastes into bio-fuel and bio-fertilizer.Straw-bed anaerobic fermentation system is a new anaerobic bioreactor for biogas production, which digests livestock wastewater and agricultural straw in one bioreactor at the same time.The straw-bed anaerobic fermentation system is composed of straw-bed bioreactor and wastewater advanced anaerobic bioreactor(USR), and effluent of straw-bed bioreactor is added as inlet into wastewater advanced anaerobic bioreactor.In straw-bed bioreactor, baling straw is used as stationary phase, and livestock wastewater is used as mobile phase.Our previous study indicated that co-digested baling straw and swine wastewater in straw-bed anaerobic digestion system was feasible and beneficial for biogas production.However, in straw-bed bioreactor, baling straw floated upward and inlet short flow appeared in the late stage.In order to solve these problems, gas guide tube was added in baling straw and reserve buffer space at the bottom of straw-bed bioreactor and the combination of the two methods were set up.There were four treatments in the study, i.e.CK (No improvement measures), adding guide tube (GT), buffer space (BS) and guide tube + buffer space (GT+BS).Meanwhile, effect of improvement measures on biogas production, and COD (Chemical Oxygen Demand)removal rate of straw-bed fermentation system were conducted.The results showed that daily biogas yield of CK was significantly inhibited during the first 25 days (organic loading rate of swine wastewater was less than 2.13 kg/(m3/d)) which was much lower than that of the other treatments.However, after 25 days' reaction, there was no significant difference of daily biogas yield between control and other treatments.By adding improvement measures, fermentation environment was ameliorated and the stability of daily biogas yield was enhanced obviously.After 50 days' reaction, cumulative biogas yield and cumulative methane yield of GT, BS and GT+BS were 18.90%, 9.05%, 22.48%, 23.02%, 9.34% and 25.21% higher than that of CK, respectively.Wastewater advanced anaerobic bioreactor (WAAB) is an important part of straw-bed fermentation system.The gas production results showed that, there was no significant difference for that of CK and the other treatments with the gas composition of WAAB.All treatments had the average methane content of 68%.Meanwhile, there was almost no significant influence on cumulative biogas yield, average methane content and COD removal rate of the straw-bed anaerobic fermentation system by adding improvement measures.The above results indicated that adding gas guide tube to straw-bed bioreactor was beneficial to improve biogas production, methane content and gas stability, adding buffer space can also be considered as conditions permit.