The hydroites of meteorites mostly are in matrix of carbonaceous chondrites. Their major phases are phyllosilicates, and hydroxides, carbonates and sulfates are minor phases. Based on the relation of hydroites and anhydrous minerals, the relation of hydroites and organic matter, the reactions of water vapour and anhydrous minerals in nebular,and isotopic composations of chondrites, we concluded that aqueous alteration occurred during nebular condensation. Through comparative study on oxygen isotopic composition and water content of chondrite groups, and the fact that water or water ice exists in terrestriial planets,such as Earth, Mar, Mercury and Moon, we infer that the space range of nebular aqueous alteration involve terrestrial planet region and astroid region of nebular disk. Therefore the source of water in Earth must be with nebular aqueous alteration.