The invention discloses a mobility management method used for an intelligent traffic system. The mobility management method comprises the step of cell reselection: cell reselection is triggered by monitoring the channel quality measurement values of a serving cell and neighboring cells under the idle mode; and the steps of air interface switching: the switching program includes channel measurement, switching trigging, switching judgment and switching preparation and switching performance. The invention also provides a mobility management system used for the intelligent traffic system. According to the technical scheme, a fast and smooth mobility management mechanism between RSU can be realized so as to guarantee reliable service transmission in the terminal mobile process, adapt to the high speed mobility of the terminal, overcome the instability of wireless links and meet the QoS demands of upper services.