The invention discloses a green fertilizer capable of improving soil and a preparation method thereof. The green fertilizer is prepared from the following raw materials in parts by weight: 30-50 parts of animal giblets, 15-20 parts of wheat bran, 12-18 parts of furfural residue, 10-15 parts of bark, 14-22 parts of Chinese medicine residue, 11-19 parts of manioc waste, 8-16 parts of flax seed meal, 5-10 parts of manganese slag, 5-10 parts of plant ash, 6-12 parts of oyster-shell powder, 10-15 parts of leaf mould, 5-10 parts of crushed crude pearlite, 4-8 parts of cologne acid mother liquor, 10-15 parts of tung greensand, 5-10 parts of stone fine grain, 10-15 parts of modified attapulgite, 3-5 parts of chitin oligosaccharide, 2-4 parts of alum powder, 15-20 parts of ammonium sulfate, 10-15 parts of monopotassium phosphate,1-2 parts of ferrous sulfate, 0.5-1 part of sodium borate, 1-2 parts of zinc sulfate and 0.5-1 part of ammonium molybdate. By adopting the green fertilizer capable of improving soil disclosed by the invention, the organic matter of the soil can be increased, the soil fertility is improved, meanwhile, the soil structure also can be improved, the soil pests are prevented and treated, the phenomena of soil degradation, soil fertility reduction and soil hardening are effectively improved, and healthy and quick growth of green plants is facilitated.