In order to improve the system performance of visual-inertial simultaneous localization and mapping (VISLAM)system,an optimization method for positioning accuracy and tracking stability of monocular visual inertial odometry(VIO)is proposed.In the camera pose optimization stage,in order to improve the positioning accuracy of the system,the camera pose is optimized through multiple residual items.When feature tracking is lost,in order to improve the tracking stability of the system,the integral information of inertial measurement unit(IMU)and the depth enhancement method of feature point are used to relocate the system.The proposed method is improved based on the ORB-SLAM3 code framework,and the feasibility of the method is verified in open source data sets and real environments.The experimental results show that the proposed method can effectively improve the positioning accuracy and tracking stability of the visual-inertial odometry.