A new car-following model is proposed in this paper to study the interval integration effect of vehicle’s self-delayed velocity information on traffic flow. The stability condition of the new model is derived through linear analysis, and the result shows that the traffic stability can be improved when a longer interval of vehicle’s self-delayed velocity information is taken into account. Also it is revealed that the traffic information in the time interval which is far from the present time is more positive in stabilizing traffic flow comparing to the traffic information in the time interval which is close to the present time. Through nonlinear analysis, the mKdV equation is derived to describe the propagation properties of density wave in the unstable region. Finally, the theoretical results are confirmed by numerical simulation.