The application status of anaerobic sludge digestion process at large-scale wastewater treatment plants in Northern China was summarized based on survey on sludge treatment technologies used in 108 wastewater treatment plants. Among the 108 wastewater treatment plants, there were totally 27 plants using anaerobic digestion process, 9 plants were representative, only 3 of which were normally operated. The operation status of the 27 plants using anaerobic digestion process was analyzed, including the type of process, sludge quality, mode of digester, sludge mixing equipment, biogas application methods and operation management. Main problems of anaerobic sludge digestion process used at large-scale wastewater treatment plants in Northern China were discussed, and potential solutions were proposed.