The invention discloses a centralized and distributed type classified humidification central ventilation system which comprises a filtering module, a draught fan, a full heat exchanger, a central humidification module, a plurality of parallel distributed type humidification modules, an air return module, a corresponding pipe net and a valve control system. The central humidification module is the same as the distributed type humidification modules and is composed of a fogging device, a pressure-sharing liquid collecting bin, a liquid return pipe, an air valve and the like, wherein the pressure-sharing liquid collecting bin sequentially comprises an ultraviolet lamp, a liquid stopping plate, a bottom filter net and a mud control valve from top to bottom; and the air return module comprises an air return draught fan, an air return pressure sharing bin, a main air return pipe, a plurality of branched pipes, corresponding valves and other equipment. According to the centralized and distributed type two-stage humidification design principle, the humidification efficiency can be strengthened while differentiation definition of the humidity of different fresh air connection zones is carried out; and according to the centralized and distributed type classified humidification central ventilation system, air particle matter, gaseous pollutant, bacterial viruses and the like can be purified. The central ventilation system is particularly suitable for families in north during heating, and is efficient, energy-saving, safe and good in practicability.