The invention discloses a method for building a signal control model for an urban traffic network crossroad for solving the technical problem that the existing urban traffic network crossroad is complex in signal control. The technical proposal is that the signal control model of the urban traffic network crossroad is built through the relationship between discrete state equations of the crossroad and adjacent crossroads according to requirements of the traffic signal control so that correlation and restrictive relation of the whole urban traffic network model are fully embodied. The model isbuilt according to the requirements of the signal control by using the method of the invention, traffic signal timing is carried out on a single crossroad or unified optimizing timing is carried out on the whole traffic network signal lamps according to optimization indexes so as to dynamically analyze the urban traffic network, thereby simplifying the problem of the urban traffic network crossroad signal control.