Abstract: Determination of fat in food is an important part of food nutrition detection, and is an important guarantee for people's healthy diet.On December 23, 2016, the National Health Planning Commission issued the GB 5009.6-2016 "the determination of fat in food safety national standard food", which replaced 9 standards for the determination of fat in food.It is a unified and universal standard of fat testing compulsory by the state.However, because of the variety of food, the fat morphological characters are different, the principle of fat detection method is diverse, the universal standard may exist some unspecific and unsuitable conditions.In this paper, by comparing the principle, scope and process of fat detection in the literature of substitutes and fat testing, the key points of controlling the sample, sampling, extraction and constant weight technology of the national standard for the determination of fat in food were summarized.