Abstract: The organic matter content of food waste is high and can easily cause system acidification and suspension in the process of anaerobic digestion. The anaerobic co-digestion technology to jointly treat food waste and sewage sludge was studied, which could well solve the difficulty of controlling the food waste digestion conditions. The results showed that the anaerobic co-digestion of food waste and sewage sludge could run steadily when the total solid(TS) content of the feeding waste was about 10%, hydraulic retention time(HRT) being 20 d, and alkalinity controlled between 6 000-8 000 mg/L. And under these conditions, the organic loading rate reached 5.29 g/(L•d), the biogas production rate reached 1.03 L/g (calculated by volatile solid(VS)) and the methane content in biogas was more than 59%.