In this paper, we adopt the classification of personal information and hierarchy of services to build a privacy system, in which one communicates with each other via pipes with different security levels. In each level, one has the corresponding rights to access each other. The requesters are not able to be infringed based on the personal information that service obtains from service providers. Privacy system can decrease the interaction, while in other circumstance the system strengthens and enhances the privacy preserving. Thus we strike a balance between two goals of Ubiquitous Computing: interaction and privacy preserving.