The present invention consists of masato and sand or soil containing a large amount of stone, etc. Soil (1400) for rapid infiltration and evaporation of moisture, and dry soil around the roots in which outdoor plants and trees are exposed to the natural environment for a long time ( 1410) In order to maintain moisture in the wet soil (1420) so that the plant growth requirements are satisfied, etc., the water absorbent (140) is absorbed and stored inside the wet aggregate (1300) molded from the mortar cement (410) It relates to a method of manufacturing a wet type aggregate for land reclamation, which is made of mortar cement which has secured a space in which the) is embedded. To this end, the present invention is a water absorbent foundation having a function of providing moisture to the soil of the dry soil around the wet aggregate 1300 in a state in which water impregnated in the soil 1400 is absorbed and stored in the water absorbent 140. Step 100； An outer formwork coupling step 200 in which a through body 220 connected to a plurality of square rods penetrating the side surface of the main body 210 is coupled to a main body 210 formed of a plurality of grid-shaped square frames； An inner formwork mounting step 300 of mounting the inner formwork 320 formed of a plurality of rod rods 310 to the outer formwork 230 in which the through body 220 is coupled to the main body 210； A mortar cement injection step 400 of injecting mortar cement 410 in a state where the inner mold 320 is mounted on the outer mold 230； After the injection of the mortar cement 410, the curing proceeding step 500 to cure in the shade until the moisture content is 7% to 10% or less； A through-body removal step (600) for separating the through-body 220 at a low speed in a state in which the moisture content of the mortar cement (410) is 7% to 10% or less in the curing proceeding step (500)； After curing the through body 220, the primary curing is completed until the moisture content is less tha
