The invention discloses high-strength nonwoven geotechnical cloth, and belongs to the field of textiles. The high-strength nonwoven geotechnical cloth is prepared from, by weight, 30-40 parts of modified carbon fibers (with the length of 60-80 mm) and 40-50 parts of modified polyacrylonitrile fibers ( with the length of 70-90 mm); the modified carbon fibers and modified polyacrylonitrile fibers are mixed and subjected to opening to obtain mixed fibers, the mixed fibers are put in a lapping machine, after being processed by the lapping machine, the mixed fibers are put in a needle machine, needling treatment is conducted according to the needling density of 100 needles/cm2, pre-treated geotechnical cloth is obtained, after being soaked in a potassium permanganate solution, the pre-treated geotechnical cloth is washed and dried, and the high-strength nonwoven geotechnical cloth is obtained. The prepared geotechnical cloth has high mechanical strength and good permeability.