Hand gesture based Human-Computer-Interaction (HCI) is one of the most natural and intuitive ways to communicate between people and machines, since it closely mimics how human interact with each other. In this demo, we present a hand gesture recognition system with Kinect sensor, which operates robustly in uncontrolled environments and is insensitive to hand variations and distortions. Our system consists of two major modules, namely, hand detection and gesture recognition. Different from traditional vision-based hand gesture recognition methods that use color-markers for hand detection, our system uses both the depth and color information from Kinect sensor to detect the hand shape, which ensures the robustness in cluttered environments. Besides, to guarantee its robustness to input variations or the distortions caused by the low resolution of Kinect sensor, we apply a novel shape distance metric called Finger-Earth Mover’s Distance (FEMD) for hand gesture recognition. Consequently, our system operates accurately and efficiently. In this demo, we demonstrate the performance of our system in two real-life applications, arithmetic computation and rock-paper-scissors game.