A vehicle safety system includes an obstacle detecting device for detecting an obstacle around a vehicle; a vehicle state detecting device for detecting states of a speed, acceleration, turning sideways, sudden braking, sudden revolving, sideslipping and the like of the vehicle; a dangerous degree determining device for determining a dangerous level of the obstacle with respect to the vehicle or dangerous level of the vehicle itself by receiving information from the obstacle detecting device and/or the vehicle state detecting device; a seat belt device for changing a shape, including an area of a belt, of a touching portion where the belt touches an occupant according to dangerous level information from the dangerous degree determining device; and an occupant identifying device for storing physical characteristics of the occupant sitting on a seat corresponding to the seat belt device. The seat belt device receives information from the occupant identifying device, and changes the shape of the touching portion according to the physical characteristics of the occupant on the seat. Thus, the vehicle safety system provides the occupant with a warning and more suitable protection by estimating a dangerous degree of the obstacle or problem.