Diet contributes to the increasing incidence of chronic diseases. Thus, fast, accurate, and convenient dietary assessment tools are in demand. We designed an internet-based diet and lifestyle questionnaire for Chinese (IDQC). The objective of this study was to validate its applicability and assess the dietary habits of Chinese college students.Six hundred forty-four college students from northern China were recruited and asked to complete the IDQC for the last 4 months (135 food items) and 3-day diet records (3DDRs). Food and nutrient intakes recorded in the IDQC were validated against those in the 3DDRs using the Wilcoxon matched-pairs t test, correlation analysis, and cross-classification. The Student t and χ tests were used in the dietary assessment.There were significantly positive correlations in the dietary intakes of 9 food groups and 23 nutrients between the IDQC and 3DDRs. All participants consumed low levels of fruits, vegetables, legumes, dairy, and certain micronutrients (ie, vitamin A, vitamin B1, vitamin B2, folic acid, vitamin C, calcium, selenium, and iodine), and high levels of iron and manganese. Male students consumed higher intakes of the food groups and nutrients than female students.The IDQC represents an accurate and convenient dietary assessment tool that can be used in large populations. Inadequate and excessive nutrition co-existed in college students, and more fruits, vegetables, legumes, dairy, and various vitamins and minerals were needed in this population's daily diet. The IDQC is free of access at www.yyjy365.org/diet.