The invention discloses a preparation method of an organosilicon-coated aqueous aluminum pigment, and an aluminum pigment. The preparation method comprises: (1) washing of the surface of aluminum powder; (2) surface hydroxylation treatment of the aluminum powder: mixing the washed aluminum powder and an organic solvent 2, adding a treatment liquid, and carrying out surface hydroxylation on the aluminum powder; and (3) coating the aluminum powder with organosilicon: mixing the hydroxylated aluminum powder, an organic solvent 3 and a catalyst, adding the mixed liquid into a polysiloxane solutioncontaining an active reactive group in a dropwise manner, carrying out a reaction, filtering, washing, and drying to obtain the coated aluminum powder. According to the present invention, the reactive organosiloxane is used, and is subjected to grafting and condensation cross-linking at the surface of the aluminum powder so as to achieve the microencapsulation of the aluminum powder; the preparedaluminum pigment has characteristics of good water resistance, corrosion resistance and high gloss, and has good compatibility with aqueous coating material emulsions; and the method has advantages of simple reaction, low cost, industrial prospects and environmental protection.