The invention discloses a building micro-ventilation system for improving indoor air quality and humidity environment, comprising an air-supply subsystem, an air filtering device, a dehumidifying subsystem and a smart control subsystem. The building micro-ventilation system is used for providing fresh air to a building, and capable of filtering, drying and dehumidifying the fresh air according to requirements; therefore, the system is capable of effectively adjusting the indoor humidity, improving the indoor air quality environment, avoiding outdoor noise interference and preventing rainwater from entering the indoor space, guaranteeing the health and comfort of people staying in the indoor space and preventing the building and articles in the indoor space from being moisturized and mildewed; as a result, the building micro-ventilation system is suitable for improving the indoor environment of buildings such as villas, high-grade residences, hotel guest rooms and the like in humid areas, in particular for improving the indoor air quality and the humidity environment of residential buildings in central urban areas and besides heavy traffic roads.