NOVELTY - Accelerating anaerobic fermentation of sludge using zero-valent iron comprises: taking high-solid sludge; taking iron sheet; removing oil stain on the surface of the sheet and scrap the surface for removing rust; placing the sludge and scrap iron into an anaerobic fermentation reactor; mixing anaerobic microorganism and to-be-processed sludge; inoculating the microorganism and uniformly stirring the mixture; sealing the reactor, carrying out fermentation to collect methane; stirring the mixture using an electric stirrer; and carrying out anaerobic fermentation.    USE - The method is useful for accelerating anaerobic fermentation of sludge (claimed).    ADVANTAGE - The economic method is capable of promoting high solid anaerobic fermentation of sludge after reduction, and increasing amount of methane production during fermentation.    DETAILED DESCRIPTION - Accelerating anaerobic fermentation of sludge using zero-valent iron comprises: taking sludge having less than 10% of solid content; taking iron sheet and controlling surface area of the sheet to be 10 cm2; removing oil stain on the surface of the sheet and scraping the surface for removing rust after performing air oxidation for 3-5 days to generate 1-2 mm of rust on the surface; placing 1-20 g of the sludge and scrap iron into an anaerobic fermentation reactor, according to every Kg of the sludge; mixing anaerobic microorganism and to-be-processed sludge at ratio of 1:5-1:10, preferably 1:9; inoculating the anaerobic microorganism and uniformly stirring the mixture; sealing the reactor, carrying out anaerobic fermentation under the stirring state to collect methane; stirring the mixture using an electric stirrer at speed of 50-120 revolutions per minute, preferably 90-100 revolutions per minute; controlling pH of the reactor to 6-8, preferably 7 and temperature of 25-37 degrees C, preferably 37 degrees C; carrying out anaerobic fermentation under blending condition for 20-25 days, preferably 22 days; leaving the sludge and the residual scrap iron remaining in the fermentation reactor to process next batch of the sludge after fermentation process is finished.