The invention relates to a car window automatic control system and method, and belongs to the field of car control. In order to solve the problems that in the prior art, after a car enters a tunnel ora parking lot, a car window cannot be automatically closed in time, and the car window automatic control system comprises a GPS positioning module used for collecting car positioning information andaccordingly obtaining the signal-to-noise ratio of a GPS signal, and a car data communication gateway communicated with a car internal bus to obtain car window opening and closing state information; and when the signal-to-noise ratio of the GPS signal is lower than a preset threshold value and the car window is in an opening state, control information is transmitted to a car internal bus, the control signal is transmitted through a car data communication bus, and a window rising motor is controlled to rise the window. Manual operation of a driver is reduced, the driving safety is improved, thecar window automatically rises when a car is driven into a building, the frequency of car window button operation by the driver in the travelling process is reduced, and the driving risk and the accident occurrence possibility are reduced.