Building energy-saving ventilation system

The invention relates to a building energy-saving ventilation system, and effectively solves the problems that when ventilation is conducted in a building at present, due to the fact that the orientation of a traditional ventilation opening is fixed, the utilization rate of the traditional ventilation opening to external natural wind is low, and a filter screen needs to be manually and frequently cleaned. According to the technical scheme, the device comprises a ventilation pipe, a telescopic pipe, a winding assembly, a first filter screen, a second filter screen, an adjusting assembly, an adjusting plate and the like; the ventilation system can capture external natural wind in different directions and send the external natural wind into a building room (the indoor ventilation and air exchange effects are achieved), the utilization rate of the external natural wind is increased, the filter screen can be automatically cleaned synchronously with the help of the external natural wind while ventilation and air ex