Abstract: Taking tomato cultivar ‘Boyuan No.2’ as test material, seedling substrate add Clonostachys rosea and Bacillus subtilis alone or in combination method were used to study the effects of different treatments to tomato growth, yield, quality and root rot, in order to provide reference for Ningxia greenhouse tomato soil-borne disease biological control technology.The results showed that addition of Clonostachys rosea and Bacillus subtilis alone or in combination in seedling substrate could promote the growth of tomato seedlings and reduced the incidence of root rot, and the combined treatment was the best.The emergence rate and shoot height of tomato treated with the combined treatment were 97.22% and 6.67 cm, respectively, significantly higher than CK.The shoot height, root length, fresh biomass and dry biomass of tomato treated with the combined treatment were increased by 7.02%,21.53%,9.23% and 33.33%,respectively, before transplanting.The numbers of rhizosphere soil fungi and Bacillus sp.in the combined treatment were 10 times and 100 times higher than CK,respectively.After transplanting, the shoot height and stem diameter of tomato treated with the combined treatment significantly increased by 8.96% and 28.20% respectively compared with CK,while the root rot of tomato treated with the combined treatment was significantly reduced by 51.40% compared with CK.The weight of single fruit, yield per plant and yield per 667 m~2 of tomato treated with the combined treatment were 6.81%,13.97% and 15.46% significantly higher than CK,respectively.The soluble sugar content and sugar-acid ratio of tomato treated with the combined treatment were significantly increased by 17.08% and 46.38% respectively compared with CK.In conclusion, the addition of 0.1 g of Clonostachys rosea agent and 2 g of Bacillus subtilis agent per kilogram of seedling substrate had better disease control and tomato growth promotion effect.