A vehicle management system and method in a telematics system. The vehicle management system includes: a telematics terminal for measuring a vehicle state at each first period, accumulating and storing the measured vehicle state during a second period, and transmitting accumulated and stored accumulation vehicle state information; and a telematics center connected with the telematics terminal, and receiving the accumulation vehicle state information from the telematics terminal, storing the received accumulation vehicle state information, checking a variation progress of state values of each vehicle part of the received accumulation vehicle state information and searching for corresponding diagnosis information, and generating and transmitting vehicle management information to the telematics terminal.