Objective To explore the value of a smartphone-based augmented reality technique （Persp 3D SLAM software） in preoperative localization of superficial supratentorial tumors.Methods Ten patients with superficial supratentorial tumors （2.3 to 6.8 cm in diameter） were included. Preoperative MRI or CT data were used to perform 3D reconstruction of the tumor， head contour， nose， and bilateral auricles， which were then loaded into Persp 3D SLAM for preoperative tumor localization. Traditional manual localization was also conducted as the control. The accuracy of localization was evaluated by positioning error， which was the distance between the tumor center positioned by either method and that by neuronavigation.Results The positioning error of Persp 3D SLAM was significantly smaller than that of the traditional method （0.48±0.04 cm vs 2.08±0.23 cm， P <0.05）.Conclusion The Persp 3D SLAM software shows higher accuracy than the traditional manual method in localizing superficial supratentorial tumors， and can provide direct visualization of cortical veins and fiber tracts around the tumors， facilitating reasonable preoperative plans and minimizing surgical injuries. Keywords： supratentorial tumor； smartphone software； augmented reality； neuronavigation； preoperative localization