Abstract: Objective Whether the developed new type of radiotherapy auxiliary fixation device compatible with the head and neck joint coil can improve the quality of magnetic resonance images in radiotherapy and verify whether it can be applied to clinical treatment. Methods The clinical trial selected patients with brain metastases and nasopharyngeal cancer patients, using thermoplastic film and head and shoulder molds for posture fixation, and treatment on the ELekta Versa accelerator. SPSS 20.0 statistical software was used to analyze the data. The measurement data were expressed by X±S, and the t test was used. P<0.05 was considered as statistically significant. Results Considering the influence of the outer contour of the device, the target dose meets the clinical requirements. The setting error is less than 2 mm in the three translation directions, and the rotation error is less than 2^o in the three rotation directions. Conclusion There is no statistical difference between the treatment results of patients using the new type of fixation device and the conventional method. The target area threatens the organ dose, and the positioning error meets the treatment requirements.