Intro：Haptic Interaction Special Issue: Touch is an important channel for human beings to communicate with the external world and plays a crucial role in human interaction with nature. Information such as softness, friction, texture and warmth, or more complicated human emotional communication can only be perceived by the act of touching. Despite its importance, it is striking that haptic feeback in human-machine interaction is still in its infancy. For example, a human user can enjoy realistic visual or auditory experiences facilitated by a computer through devices such as a head-mounted display or a stereo headset. However, haptic experiences that the user can obtain is extremely limited during such interactions. Haptic interaction technology enables users to touch virtual objects and experience tactile sensations, including contact force, softness, texture, weight, vibration, and temperature. These sensations can significantly enhance users' interactive experience of virtual-reality systems. Haptic interaction technology can be applied in many fields, such as surgical simulation/ training, virtual assembly and maintenance of complex mechanical equipment such as aircraft engines, interactive entertainment experiences such as movies and computer games.