NOVELTY - Detoxication of soil contaminated with persistent toxic organic substances involves cultivating at least one or two mushroom species e.g. Pleurotus sajo caju, Lentinus edodes on substrates for creating humus; preparing ground for contaminated soil to be treated by loosening, humidifying and finely crushing the contaminated soil to be treated; adding and mixing the crushed mushroom-cultivation humus; inundating the resulting soil in 20 minutes; and treating the remaining contaminated soil and improving soil quality by seeding, growing plants e.g. legume, peanut.    USE - For detoxication of soil contaminated with persistent toxic organic substances selected from dichloro-diphenyl-trichloroethane (DDT), 2,4-dichlorophenoxyacetic (2,4-D) acid, 2,4,5-trichlorophenoxyacetic (2,4,5-T) acid, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro,1,3,5-triazine (hexogen, RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (octogen, HMX) (claimed).    ADVANTAGE - The method provides over 90% detoxification efficiency with respect to soils contaminated with DDT, 2,4-D, 2,4,5-T at the level of 50 ppm, with 2,3,7,8-TCDD at a level of 5000 ppt, with TNT, RDX and HMX at a level of 150 ppm after 30-40 days; provides over 99% after 60-70 days; and requires minimum amount i.e. 5 wt.% of mushroom cultivation humus for adding into the soil.    DETAILED DESCRIPTION - Detoxication of soil contaminated with persistent toxic organic substances involves cultivating one or simultaneously two mushroom species selected from oyster mushroom Pleurotus sajo caju, beech mushroom Lentinus edodes, fragrant mushroom Agaricus rhinozetis, lingzhi mushroom Ganoderma lucidum on different kinds of substrates for creating humus for treatment purpose until obtaining hyphaes covering the substrate bag or fungus peritheciums generated; preparing ground for contaminated soil to be treated by loosening, humidifying and finely crushing the contaminated soil to be treated; adding and mixing the crushed mushroom-cultivation humus into a particle size smaller than 2 mm into the soil prepared in a ratio of 5-10 kg humus/100 kg soil; inundating the resulting soil in 20 minutes then maintaining the humidity of 15-20% for 30-80 days; and subsequently treating the remaining contaminated soil and improving the soil quality by seeding, growing a legume, peanut, corn, sorghum in an average density not less than 100 seeds/m2 or Vetiver grass, Acacia mangium, Acacia auriculiformis in a density of 6-8 plants/m2 for 45-60 days.