Abstract: In order to solve the question of traffic congestion and traffic resources wasting caused by the density difference between freeway and auxiliary road, the method of balance control for freeway and auxiliary road based on MFAC was proposed. This method introduced the difference balanced control theory and was not restricted by the entrance ramp and auxiliary road intersection model. Only depending on the ramp and intersection traffic flow rates as input data and the density of freeway and auxiliary road sections as output data, this method could achieve the model-free adaptive control on strong nonlinear freeway and auxiliary road system, reach to density equilibrium on freeway and auxiliary road system. The simulation results on the Matlab platform showed the effectiveness of the method.