Abstract: As the final product of the wastewater treatment plant, the sludge is complex, mainly including protein, polysaccharides and other organic matter, as well as a variety of heavy metals.In this study we use of different pretreatment methods of protein extraction from sludge such as alkali, heating, ultrasonic pretreatment and EDTA, analyse the result contrastively and find a method to extract crude protein in high efficiency.Meanwhile we use Fourier transform infrared spectroscopy (FT-IR) and Inductively coupled plasma atomic emission spectrometry（ICP-OES）for further analysis of the extract,in order to validate the nutrition and safety of the extracted sludge protein as animal feed.