Studies of robot wheelchair human-robot interaction have shown that long-term use of a single mode of interaction can easily lead to misjudgment of user operation intentions and decrease of control stability. The complete autonomous mode can also cause people frustration due to the lack of user control experience. Aiming at the problems of hard mode switching and lack of dynamic adjustment ability to environmental changes in the existing robot wheelchair interaction based on human-robot cooperation, this paper uses the gesture interactive control and proposes a robot wheelchair dynamic shared control method based on the combination of user behavior and autonomous navigation. Firstly, the user's palm coordinates are tracked based on the Leap Motion sensor to generate the user's gesture speed command; Secondly, the autonomous navigation control command is generated based on RPLIDAR A1 lidar sensor and autonomous navigation algorithm; Finally, the weight of human-robot control command is updated in real time based on various constraints such as distance, fatigue and error, so as to realize the dynamic shared control of robot wheelchair. The experimental results show that the dynamic shared control method can dynamically adjust the role allocation between different modes according to the wheelchair operating environment and user operating performance, avoid the direct hard switching between different modes, and has a better user experience.