The invention provides a device for automatically opening, closing or elevating a side window of a passenger car or a bus and a working method of the device. The device comprises a driving device, N actuating mechanisms and locking structures, wherein the actuating mechanisms and the locking structures are matched with the driving device; one end of each of the actuating mechanisms is mounted at the bottom or on the side edge of the side window of the passenger car or the bus, and the other end of the corresponding actuating mechanism is connected with the driving device; the side window is movably connected with a vehicle body; N is a natural number which is equal to or larger than 1; the driving device is connected with a control switch; the control switch is connected with a vehicle-mounted computer; the vehicle-mounted computer is also connected with a fire fighting detecting device mounted on the passenger car or the bus; each of the locking structures is mounted on the corresponding actuating mechanism. When an accident occurs to the passenger car or the bus, side window glass can be effectively and quickly opened by the device, and the control switch can also be connected to a passenger door, the passenger door is synchronously opened when the control switch is on or off, so that an escape channel for passengers is extended. The device disclosed by the invention can also solve the problem of high temperature in the passenger car or the bus because of the sunsolarization of the sun for a tourism bus.