Safety is a basic requirement in any human-robot collaboration scenario. To ensure user safety, from both physical and psychological aspects, we propose a novel Virtual Barrier system facilitated by an augmented reality interface 1 . Our system provides two types of Virtual Barriers to ensure safety: 1) a Virtual Person Barrier which encapsulates and follows the user to protect them from collisions with the robot, and 2) Virtual Obstacle Barriers which users can spawn to protect objects or regions that the robot should not enter. Our system utilizes augmented reality to visually display these protective barriers to the user during operation. To enable effective human-robot collaboration, our system automatically replans the robot’s motion when potential collisions are detected as a result of a barrier intersecting the robot’s planned path. Comparing our novel system with a standard 2D display interface in a user study with a mock industrial manufacturing task showed that our system increases both physical and psychological safety, task efficiency and interaction intuitiveness.