The invention discloses an urban road network traffic control subarea dynamic partitioning method, which comprises the following steps of: 1, initializing a traffic control computer; 2, judging whether a current moment reaches to ta while not to tb yet, wherein if yes, a road network traffic state is represented to be at a trough, and traffic control subarea partitioning is not needed; and ta is the starting moment of the trough at night, tb is the finishing moment of the trough at night, and a traffic engineer confirms that the ta is 22:00 and the tb is 6:00; 3, if not, judging whether the current moment is tb or not, and if the current moment is just tb, carrying out traffic control subarea initialized portioning; 4, if the current moment is not tb, judging whether a time difference between the current moment and traffic control subarea partitioning last time is Tk or not, wherein if yes, carrying out traffic control subarea dynamic adjusting, and Tk is a traffic control subarea dynamic adjusting time interval; and 5, if the current moment is not tb, and the time difference between the current moment and traffic control subarea partitioning last time is not Tk, remaining a traffic control subarea scheme unchanged.