In order to optimize practical characterization method of rollover warning indices for truck, the theoretical analysis of correlation and dynamic simulation test validation are carried out for three kinds of rollover indices (lateral acceleration, roll angle, lateral load transfer rate). Based on the simplified roll dynamics model of vehicle, the model about three kinds of rollover index correlation is deduced, and a nonlinear multi-degree-of-freedom dynamic model with the actual parameters of a certain light truck is established in Matlab/Simulink. The two groups of step-steering with setting the vehicle speed and steering angle changing independently, is used to study the quantitative correlation of vehicle rollover indices and practical characterization methods. The linear quantification model between roll angle or lateral load transfer rate and lateral acceleration is obtained by fitting the distribution of the final stability point. It is verified that the practical characterization method of rollover warning indices that uses lateral acceleration to indirectly characterize roll angle and lateral load transfer rate is feasible. The results show that with the increase of the steering wheel angle and the vehicle speed, the roll angle, the lateral load transfer rate and the lateral acceleration can quickly be tend to stable state in the whole simulation process. The vehicle roll angle and lateral load transfer rate calculated by this method provide a good index basis for the design of the following vehicle rollover warning control system.