In such application of VR to teleoperation, the most important thing is to keep the virtual environment consistent with the real environment as most of the operating time. If this can be ensured, a good part of practical teleoperation can be performed in an automatic way. Following this idea, we have developed a model-based dynamic calibration algorithm for the consistency of the two environments. First, model of the real environment is created by moving a camera through the environment. We use multi-position-based stereo vision technique. In the process of rehearsal, path is planned by the operator for a specific task. In such case, places that have complex structures for teleoperation such as turning corners, narrow spaces, etc. are defined as key positions by the operator, where local landmarks are set for later dynamic calibration. During practical teleoperation, the robot moves through the planned paths for all the areas except the selected key positions. At key positions, 3D positions of the robot are calibrated by matching features of the landmarks in the images and their corresponding features in the models interactively. Errors detected between the virtual and real environments are recorded to amend the planned path for the coming robot movements. When the robot is approaching near the target, it will be difficult for the operator to determine accurate position of the target in teleoperation. We propose and implement a marker-based algorithm for automatic location of the target at such case. Preliminary experiments have been carried out using a setup consisting of a 4 DOF movable platform, a camera and a laser gun mounted on the platform. Several small cubes are used as landmarks and placed in a room-like environment with several polyhedrons as obstacles. The target is a laser-light-receiver placed inside a small hole on a planar surface of arbitrary pose. The task is to shoot a laser beam from the laser gun into the receiver. The experimental result was quite satisfactory.