On-ramp metering is an effective tool for traffic management on freeway networks． In this paper，based on the ordinary differential equation( ODE) model of the ramp system，a new fuzzy self-tuning PI controller for freeway ramp metering is designed． By considering the upstream and downstream traffic flow information sufficiently，the designed PI controller can effectively suppress the influence of the system disturbances． Furthermore，a fuzzy logic is esigned to tune of the PI controller parameters automatically． Compared with both PID and ALINEA approaches，the simulation results illustrate the validity and efficiency of the presented method intensively．