To provide a granulated peal moss by granulating the peal moss material without any additive without deteriorating its ion exchangeability or adsorptivity and allowing it to retain not only the useful characteristics such as a humus-supplying ability of peat moss humus or a fertilizer retention ability but also an air permeability and an water permeability by maintaining its particle shape for a long time, its use as a soil conditioning material which has a slow-released ion exchangeability and persistent adsorptivity, prevents soil pollution or environmental pollution caused by use thereof, prevents environmental pollution caused by fertilizer run-off and improves polluted soil and a preparation process thereof.

Peat moss mined from lake wetland, wherein its water content is adjusted to from 70% to 75%, is crushed and added with only fresh water to prepare an additive-free granulated peat moss with a predetermined particle size. After adjusting the water content of the peat moss mined from lake wetland to about from 70% to 75% by leaving it at an ordinary temperature or by pressurizing it, the humic fiber is crushed into about from 2 mm to 3 mm, subsequently granulated to particle diameter 6 mm or smaller in a granulator and then artificially dried to adjust its water content to from about 35% to about 60%.