In response to the specific requirements of nutrition research, Schwingshackl’s research group developed the NutriGrade grading system, which independently assessed the quality of evidence in randomized controlled trials and cohort studies in nutrition, aiming to summarize the associations or effects between different nutritional factors and outcomes and meet the specific needs of evidence users. It has the advantages of novel classification, quantifiability, independence and pertinence, and it has better consistency, fairness, reliability and feasibility. Well-designed prospective cohort studies are more feasible in the field of nutrition than randomized controlled trials. The grading of the evidence quality for cohort studies included the following eight items: a) risk of bias, study quality, and study limitations; b) precision; c) heterogeneity; d) directness; e) publication bias; f) funding bias; g) effect size; and h) dose-response. Based on the evaluation results of the above items, the evidence quality could be divided into four grades: high (8-10), moderate (<8), low (<6), and very low (<4). The purpose of this paper was to introduce the basic principles, specific contents, and application methods of the NutriGrade grading system for cohort studies and cite examples to provide references for relevant researchers.