The invention relates to mixed application technology of a compound micofume (DZ, whose common name is dazomet) and 1,3-dichloropropene (1,3-D) for controlling root-knot nematodes, soil-borne pathogenic fungi, and weed activity. The mixed application technology is suitable for pre-seeding soil disinfection of crop fields of vegetables, strawberries, flowers, gourds, nurseries, orchards, tea gardens, vineyards, forest trees, Chinese herbal medicines, and the like, and can effectively control southern root-knot nematodes, main soil-borne pathogenic fungi, main gramineae and broad-leaf weeds, and the like.