Fast-paced city life, people have no time to make friends by traditional methods. Appreciated when we encountered a stranger in the public place, but do not know each other, we have no effective way to understand each other.The study survey on making friends behavior,research on the 3G mobile application development technology, put forward a more immediate and more private mode to making friends. Propose out a mobile instant messaging software using Bluetooth technology blueprint. The study opened up a more direct and open innovational making friends mode compared with the other online instant messaging software. The study is innovative and has significant commercial value. The obtained theory and experience can be a meaningful reference to other studies in relevant fields.