OBJECTIVE: This study aimed to analyze the effects of different nutritional support methods on nutritional status and immune function of patients undergoing radiotherapy for head and neck cancer (HNC). METHODS: Patients with HNC were divided into the control (nutritional counseling and routine dietary guidance), parenteral nutrition (PN) (PN support on top of the control group), enteral nutrition (EN) (EN support on top of the control group), and EN + PN (EN combined with PN and routine dietary guidance) groups. After nutrition evaluation, the four groups were subjected to radiotherapy and nutritional support. Body mass index (BMI), serum albumin (ALB), prealbumin (PA), transferrin (TRF), hemoglobin (Hb), CD RESULTS: The four groups experienced some degree of malnutrition during radiotherapy and the EN + PN group possessed the lowest degree of malnutrition. After radiotherapy dose irradiation completion (T1), the PN, EN, and EN + PN groups possessed improved BMI (21.42 ± 1.62, 21.40 ± 1.68, 22.98 ± 1.87 vs. 20.18 ± 1.32), serum ALB (31.59 ± 3.49, 32.24 ± 4.23, 37.58 ± 3.23 vs. 26.67 ± 3.03), PA (182.63 ± 13.57, 183.43 ± 14.19, 201.59 ± 10.53 vs. 165.36 ± 20.13), TRF (162.46 ± 24.34, 157.36 ± 18.58, 182.36 ± 20.37 vs. 137.56 ± 23.19), and Hb (128.54 ± 9.21, 125.36 ± 10.23, 140.26 ± 7.23 vs. 103.24 ± 9.47) levels, higher CD3 CONCLUSION: PN and EN, alone or in combination, can improve the nutritional status, immune function and quality of life of patients undergoing radiotherapy for HNC, and PN combined with EN has the best improvement effect.