Abstract: Considering most existing work on immersive virtual reality is based on local environment, and there are still gaps and deficiencies when it comes to global-wide scenes, an interactive exploration method for digital earth is proposed aiming at the usages in immersive virtual reality. Firstly, by discussing the basic paradigms for viewpoint resolving, the observer-centered principle is established. Secondly, 2 kinds of corresponding relations among device coordinate system, geodetic coordinate system and spatial Cartesian coordinate system are derived, which can map the activity space in real world into digital earth properly. Thirdly, considering current hardware, an earth exploring method with head mounted display and controllers is developed, which can precisely manipulate the heading direction, moving direction and moving speed, meanwhile is intuitive and easy to use. Finally, the effectiveness, rationality and comfort of exploring method is evaluated by completeness, time consuming, drift angle of sight and other indexes in various types of tasks, with a multi-scale digital earth environment constructed by combining terrain images, elevation, and high-precision 3D model of oblique photogrammetry. Experiments show that the proposed method can let users travel and observe in digital earth, and complete various kinds of exploring tasks in a more natural, flexible and immersive way, which can support further research about immersive virtual reality in global-scale environment.