Abstract: Objective To understand nutritional knowledge and associated factors among Li nationality students in the "Student Nutrition Improvement Program" carried out in undeveloped counties in Hainan Province.Methods By multistage sampling,1 826 Li nationality students from grade 3 to 9 in the "Student Nutrition Improvement Program" from undeveloped counties in Hainan Province were randomly enrolled in the study.Nutritional knowledge questionnaire survey was conducted among all students.Results The average score of the nutritional knowledge was (3.15 ± 1.71) points.Nutritional knowledge score showed significant differences in gender,grade,school meal providers,knowledge sources,boarding in school,left-behind children and area (t/F were-4.676,-6.692,7.645,93.074,3.194,-3.348 and 6.014,P<0.01).Multiple regression analysis showed that grade,meal providers,gender,family population and area was main risk factor for nutritional knowledge.Average rate of nutritional knowledge awareness was 45.06%.Most of children were familiar with "iron-rich food to prevent anemia" and "vitamin-and mineral-rich food",while few of them were aware of "factors affecting height".The main source for students to acquire nutritional knowledge was campus publicity or classroom teaching(42.7%),parents or family (41.2%) and textbooks (38.7%).Conclusion Li nationality primary and middle school students in the "Student Nutrition Improvement Program" from the undeveloped counties in Hainan Province are lack of proper nutritional knowledge,grade,school meal provider,gender,family population and area plays a vital role.Targeted nutritional health education practice should be taken to improve students' nutritional awareness.