The invention discloses a dosing aeration system for water body purification. The dosing aeration system comprises a water storage tank to be treated, a uniform dosing and mixing tank, an aeration tank and a settling pond, wherein the water outlet end of the water storage tank to be treated is communicated with the water inlet end of the uniform dosing and mixing tank through a communicating tube;the water outlet end of the uniform dosing and mixing tank is communicated with the water inlet end of the aeration tank through a first water guide tube; a first water pump is arranged on the firstwater guide tube; the water outlet end of the aeration tank is communicated with the water inlet end of the settling pond through an effluent sucking tube; an effluent sucking pump is arranged on theeffluent sucking tube. Water in a stirring cavity and a liquid outlet annular cavity of the dosing aeration system is at a continuous rotational disturbance state, and thus a precipitant can be sufficiently mixed with sewage.