Abstract: An approach to registering 6-DOF electromagnetic tracker for stereoscopic virtual environment is proposed. To put tracking sensor with certain posture at a known point in real space, its position and orientation values in screen coordinate system and electromagnetic tracker coordinate system are caught. According to the values, the transformation matrix between these two systems can be calculated. Then the registration is realized, and the outputs of tracker can be transformed into coordinate values in screen coordinate system in real time. Experiments showed that the proposed approach is of low-cost and simple. In addition, the error is less than 10mm, and meets the requirements of natural manipulation of multi-sensory virtual reality system.