Abstract: An instant communication system comprising an instant communication server, a plurality of mobile terminals, and a communication network is provided; the instant communication server includes an instant communication server processor and an instant communication server memory electrically connected to the instant communication server processor; each of the mobile terminals includes a terminal central processor, a terminal communication processor, a display unit, a terminal memory, and at least one information storage unit configured for storing a CID (Calling ID); the terminal central processor is electrically connected with the display unit and the terminal communication processor respectively; the terminal communication processor is further electrically connected with the information storage unit to obtain the CID. The following advantageous effect can be achieved: communications using different phone numbers of one mobile terminal can be distinguished from each other.