The invention discloses a method and system for connecting a vehicle with an in-vehicle mobile terminal, and the system comprises a road side unit, a mobile terminal positioning unit, a background information processing unit, and a mobile terminal. The road side unit is used for obtaining the vehicle identification information and vehicle position information. The mobile terminal positioning unit is connected with the mobile terminal through a wireless network, and is used for obtaining the account information of the mobile terminal and the position information of the mobile terminal. The background information processing unit is connected with the road side unit and the mobile terminal positioning unit, and is used for obtaining and processing the vehicle information and the information of the mobile terminal and correlating the vehicle information and the information of the mobile terminal. Through the mature positioning technology, the method and system enable the vehicle to be connected with the in-vehicle mobile terminal, and then a background service management system can achieve interaction with the in-vehicle mobile terminal through a wireless network. The system can provide excellent service for persons in the vehicle, saves the cost, and is operable.