With the rapid development of computer, communication, and sensing technology, our living space has been transformed from physical space into a space shared by physical space and cyberspace. In the light of this fact and based on analyzing the char- acteristics of physical and cyberspace, respectively, this paper proposed that there are dual relations be- tween physical space and cyberspace. Establishing dual relations is realized in the following two processes: the process of information extraction, analysis and structurization from physical space to cyberspace and the process of providing the information services from cyberspace to physical space by means of inferring the intention, state and demand of users, as well. HCI (Human Cyberspace Interaction) in dual space means to establish the dual relations, which embodied the human centered HCI, i.e. the interaction is carried out in the way accustomed to users and without distract- ing their attention. With the rapid development of computer, communication, and sensing technology, our living space has been transformed from physical space into a space shared by physical space and cyberspace. In the light of this fact and based on analyzing the char- acteristics of physical and cyberspace , respectively, this paper proposed that there are dual relations be- tween physical space and cyberspace. Establishing dual relations is realized in the following two processes: the process of information extraction, analysis and structurization from physical space to cyberspace and the process of providing the information services from cyberspace to physical space by means of inferring the intention, state and demand of users, as well. HCI (Human Cyberspace Interaction) in dual space means to establish the dual relations, which embodied the human centered HCI, ie the interaction is carried out in the way accustomed to users and without distract- ing their attention.