Abstract: Objective To explore the value of mixed reality (MR) technology to assist the surgical treatment process of cranial brain tumours. Methods 59 patients with craniocerebral tumours diagnosed and treated by the Department of Neurosurgery of the Third Affiliated Hospital of Kunming Medical University from October 2022 to December 2023 were collected, and the craniocerebral tumours were randomly divided into the MR technology group and the conventional surgery group. 27 cases were enrolled in the MR technology group, and the patients" tumours were all visualized using 3D slicer in combination with the mixed reality technology to locate the tumour position, design the skin incision, and improve the preoperative planning before surgery. The conventional surgery group was treated according to the surgeon"s surgical experience. Intraoperative bleeding, operation time, bone flap area, postoperative hospital stay, postoperative complication rate and other indexes of the two groups were collected and statistically analysed to draw the corresponding conclusions. Results 27 cases were enrolled in the MR technique group, 15 cases of meningioma, 2 cases of metastasis, 1 case of acoustic neuroma, 6 cases of glioma, and 3 cases of haemangioma; 32 cases were enrolled in the conventional surgery group, 16 cases of meningioma, 9 cases of metastasis, 2 cases of acoustic neuroma, 3 cases of glioma, and 2 cases of haemangioma.The mean age of the MR technique group was 50.37±11.731 years old, and there were 8 cases of males and 19 cases of females, and the median volume of the tumour was 6.57 (2.28, 26.43) cm3 , preoperative neurological dysfunction in 9 cases, the median preoperative KPS score was 90 (80, 90), the median duration of surgery was 235 (180, 315) minutes, and the median intraoperative haemorrhage was 300 (100, 650) ml; in the group of conventional surgery, the average age was 53.34±9.143 years, with 11 males and 21 females. 21 females, the median tumour volume was 7.12 (3.57, 17.15) cm3, preoperative neurological dysfunction in 11 cases, the median preoperative KPS score was 80 (72.5, 90), the median duration of surgery was 236.5 (188.75, 290.75) minutes, and the median intraoperative bleeding was 300 (170, 587.5) ml. Statistical analysis of the above indicators revealed that the p-value was greater than 0.05 and there was no statistical difference.The median bone flap area in the MR technique group was 20.92 (15.29, 28.54) cm2 and in the conventional surgery group the median bone flap area was 33.42 (20.24, 39.95) cm2 , p-value 0.016.The median postoperative hospital stay in the MR technique group was 11 ( 8, 15) days, and the median postoperative hospital stay in the conventional surgery group was 16 (13, 18.75) days, with a P value of less than 0.001. The incidence of postoperative complications in the MR technology group was 11.1%, and the incidence of postoperative complications in the conventional surgery group was 40.6%, with a P value of 0.011. Conclusion MR technology-assisted cranial and cerebral tumour surgical treatment can achieve the functions of visualization of tumours, assisted localization, formulation of surgical plan, simulation of surgery and other roles, which is of great significance in achieving the maximum degree of safety in the resection of tumours.