The present invention provides a soil which is environmentally-friendly and exhibits excellent durability, and a method of constructing the ground of a river using the same. The method of constructing the ground of a river by using an environmentally-friendly amendment agent including SiO_2, CaO, Al_2O_3 and Fe_2O_3 comprises: a step of cutting the perimeter of a foundation to be constructed to a designed height; a step of collecting the cut foundation soil; a step of compacting the cut part; a step of mixing the collected foundation soil and an amendment agent and stirring the mixture; a step of carrying the stirred soil and spreading the stirred soil; a step of compacting the spread stirred soil; and a step of greening the compacted stirred soil. The method of constructing the ground of a river makes the soil amendment agent have the weight ratio of 6% when the foundation soil and soil amendment agent have a moisture content of 30% or less per one foundation, and makes the soil amendment agent have the weig
