OSG multi-touch natural user interface framework is based on the Windows multi-touch technology, in which the management and processing of touch event combines with OSG event processing mechanism, and forms the OSG multi-touch operation framework. According to the raw data that is produced by user's finger through touching screen, it defines the gestures needed, and combines it with interactive event processing in OSG to complete multi-touch for interactive operation in 3d scene. Based on the above framework, this paper analyzes the major operation tasks in 3D user interaction, defines the interactive gestures that conform to cognition of the 3D spatial operations, and designs the recognition algorithm of the related gestures. Finally, through developing an application example, the correctness and feasibility of design and cognition of multi-touch natural user interface framework in OSG are verified.