Abstract: The inhibition effects and the disease-control efficiency of Allium tuberosum root extracts on Foc4(Fusarium oxysopoyum f.sp.cubence race 4), and root extracts effects on soil microbial ecology were studied by bacteriostatic experiment (mycelia growth rate method, spore germination method and pot trial). The results of bacteriostatic test indicated that A. tuberosum root extracts had significantly inhibition action on mycelia growth and conidium germination of Foc4, showing concentration effects on Foc4. In addition, the aberration of the morphology of mycelia and conidium of Foc4, which were impacted by A. tuberosum root extracts, was found by microscopic observation. The results of pot trial showed that the occurrence of banana fusarium wilt decreased significantly by A. tuberosum root extracts, and disease-control efficiency increased with the increase of root extracts concentration. When the root extracts concentration reached 160 mg·mL^-1, the disease-control efficiency was up to 53.66%. A. tuberosum root extracts could affect the numbers of Foc4 and the main microorgnanisms in the soil, which was presented as the numbers of Foc4, fungi and actinomyces in the soil were reduced, while the numbers of bacteria in the soil increased evidently. The Biolog analyses on the 40th planting days showed that A. tuberosum root extracts could noticeably increase carbon source utility by microbes and soil microbial community diversity, richness, uniformity, which manifested that A. tuberosum root extracts could adjust soil microbial community structure, enhance soil microbial ecological system stability and inhibition of disease, thus reducing the occurence of soil born disease.