Provided is a method for preparing a fenugreek extract, including the steps of: (1) preparing a fenugreek plant tissue, soaking the fenugreek plant in water from 0.5 hour to 5 hours and between 25° C. and 100° C. for extraction, and (2) filtering the extracted fenugreek plant tissue to obtain the fenugreek extract. Also provided is an active substance that comprises the fenugreek extract obtained by the method. Also provided is a pharmaceutical composition for preventing or treating nonalcoholic fatty liver disease, which comprises the active substance and a pharmaceutically acceptable carrier.
