Abstract: The curve profile passing analysis is an important aspect for oversize cargo vehicle group to pass the curve safely. The curve profile expression model and the contour function expression of oversize cargo vehicle group are established based on the geometric conditions of the curve and the data of the vehicles. Based on the analysis of the requirements of passing curve profile, a safe trajectory optimization model for oversize cargo vehicle group was established with the minimum steering wheel Angle as the objective function. It was solved by genetic algorithm and simulated by Trucksim-Simulink. The simulation results show that oversize cargo vehicle group can pass the curve safely, which verifies the effectiveness of the model and algorithm.