The invention relates to the field of online social interaction, in particular to a social interaction system based on a hand-held terminal. The social interaction system comprises a user register module, a location module, a contact person module, a virtual community module and an information transmission module, wherein the information transmission module is used for building communication between a user and an contact person in a contact person list and performing information transmission through an information transmission carrier, and is also used for building communication between contact persons in a virtual community and performing mutual information transmission through an information transmission carrier. According to the social interaction system, unexpected contact persons can be added through an adding manner of rubbed shoulders, so that the problem of the single communication target in the prior art is solved, expression mode and fun are improved during the communication of users which are contact persons of each other, the problem of simple and permanent communication modes is solved, the communication between an individual and a group is improved, the communication effect of the social interaction system is improved, and the problem of obstacles of early communication between strangers is solved, so that information transmission is accepted for the other person more easily and the communication effect of the social interaction system is improved.