In order to improve the intelligent level and security of mobile robot autonomous navigation system, an autonomous navigation system based on Soft Actor-Critic algorithm under the security barrier mechanism was pro-posed to make the robot more intelligent. The return function based on the distance between the robot and the nearest obstacle, the distance from the target point and the yaw angle was designed. In the gazebo simulation platform, a mobile robot with lidar and its surrounding environment were built. Experiments showed that the security barrier mechanism reduced the probability of robot hitting obstacles to a certain extent, improved the success rate of navigation, and made the mobile robot autonomous navigation system based on Soft Actor-Critic algorithm have higher generalization ability. The system still had the ability of autonomous navigation when changing the origin and destination or even changing the static environment to dynamic.