Objective We attempted to understand the status of vitamin (Vit) A, D, and E in children aged 0–6 living in the Tibetan plateau areas of Ganzi prefecture, to provide the basis for relevant government departments to carry out physical examinations of these children and to prevent and cure four key diseases (Infantile diarrhea, nutritional anemia, rickets, and infantile pneumonia). Methods Serum retinol and tocopherol levels were detected using high‐performance liquid chromatography (HPLC). Serum levels of 25‐(OH)D were detected by high‐performance liquid chromatography–tandem mass spectrometry (LC–MS). The polynomial logistic regression was used to analyze the effects of age, season, altitude, and gender on Vit A, D, and E levels. Results Vit A and D had the lowest mean serum levels before the age of 1 year and with the most significant deficiency rates. The lowest Vit E levels were seen in the Toddlerhood group. The rates of deficiency and insufficiency were the highest. Vit A, D, and E levels were significantly affected by seasonal changes and were significantly higher in the summer than in any other season. Vit A and D were significantly affected by altitude, and their levels were lowest above 4 km. Conclusion The overall levels of Vit A, D, and E in children aged 0–6 in the Tibetan plateau areas of Ganzi prefecture were lower than those in the plain's areas.