NOVELTY - Preparation of a sewage sludge fertilizer comprises mixing sludge, ferrooxidans, and sulfur oxide in a stirring tank (1), and dehydrating; adding plant ash to the sludge, uniformly mixing, adding crushed EM cells, and fermenting at 20-25 degrees C for 15-20 days; crushing the fermented product, filtering out impurities, adding magnesium sulfate and ammonium sulfate, uniformly mixing, and drying at 160 degrees C for 30 minutes; adding 1 wt.% calcium nitrate, 0.4 wt.% magnesium sulfate, and 0.4 wt.% ammonium phosphate, uniformly mixing, and granulating; and sieving, packaging, and warehousing.    USE - Method for the preparation of a sewage sludge fertilizer (claimed).    ADVANTAGE - The method greatly reduces sludge's cost to make it into organic inorganic compound fertilizer.    DETAILED DESCRIPTION - Preparation of a sewage sludge fertilizer comprises:    (A) placing sludge, ferrooxidans, and sulfur oxide in a stirring tank (1), where the weight of sludge, ferrooxidans, and sulfur oxide is 1:1:1, slurry pump circulating stirring, and dehydrating to obtain a moisture content of 70-80%;    (B) adding plant ash to the sludge, where the weight ratio of the plant ash and the sludge is 1:4, uniformly mixing, adding crushed 20% EM cells, and fermenting at 20-25 degrees C for 15-20 days;    (C) crushing the fermented product, filtering out impurities, adding 2 wt.% magnesium sulfate and ammonium sulfate, uniformly mixing, and drying at 160 degrees C for 30 minutes;    (D) adding adding 1 wt.% calcium nitrate, 0.4 wt.% magnesium sulfate, 0.4 wt.% ammonium phosphate, 0.5 wt.% ammonium sulfate, 0.5 wt.% potassium nitrate, 0.002 wt.% manganese sulfate, 0.001 wt.% boric acid, 0.004 wt.% disodium EDTA, 0.001 wt.% ammonium sulfate, and 0.001 wt.% copper sulfate to the dried fermented product, uniformly mixing, and granulating; and    (E) sieving, packaging, and warehousing.    An INDEPENDENT CLAIM is included for a fertilizer production device, comprising a stirring tank, a concentrating and dehydrating machine (2), a stirring mill (8), a fermenting tank (4), a crusher (3), a roller type sieve (6), a drier (9), and a granulator.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram of the fertilizer production device.    Stirring tank (1)    Concentrating and dehydrating machine (2)    Crusher (3)    Fermenting tank (4)    Roller type sieve (6)    Stirring mill (8)    Drier (9)