This study shows that Simultaneous addition of zero-valent iron and activated carbon can improve the methane production and enhance the organic matter degradation of anaerobic sludge digestion. The methane content at the 10:1 ZVI/AC ratio reached 68.8%. The addition of FeCl3 or FeCl2 is beneficial to the anaerobic digestion of high solid sludge, and can improve the methane productions. The technology can be applied to the disposal of sewage sludge.