Since Virtual Reality (VR) applications are applied with many traditional fields (e.g., education, game, shopping), the user authentication is necessary to protect privacy and security (e.g., Shoulder Surfing attacks). In this work, we design and implement an interactive sphere-like input layout for user authentication. To enhance the security, the layout of password keeps rotated dynamically, which asks users to enter different characters with slight hand movement changes. Furthermore, the layout can be rotated horizontally via touchpad of the VR controller, which can provide usability while maintaining high security. This research can enrich the knowledge-based authentication in VR.