The invention discloses a room ventilation system. The room ventilation system comprises an air inlet pipeline and an air outlet pipeline, wherein the air inlet pipeline and the air outlet pipeline respectively communicate with the inside and outside of a room. The room ventilation system is characterized in that an unpowered hood is arranged at an outer end opening, which is located outside the room, of the air outlet pipeline, and a fan which is used for assisting to ventilate is arranged on the air outlet pipeline or the air inlet pipeline. According to the room ventilation system, naturalair can be preferably used for auxiliary ventilation, so that the utilization efficiency of the natural air is improved, the energy consumption is reduced, and the room ventilation system is especially suitable for being implemented and popularized and applied to buildings in high-air areas.