Protein extracting method from defatted cotton dregs

The present invention includes the following steps: pulverizing absorbent cotton dregs, grinding, soaking and dissolving, separating to obtain filtrate and filter residue, collecting filtrate and regulating its pH value to isoelectric point at a certain temp. to make protein precipitate, separating to obtain supernatant fluid and protein pulp, making the protein pulp undergo the processes of washing and drying so as to obtain finished product protein. It is characterized by adding water in the course of grinding process, and is suitable for industrial production.