The invention relates to a wet tobacco seedling cultivating substrate which is composed of a conventional tobacco seedling cultivating substrate and bacterial manure with the content of viable organism of more than (2-4)*10 to the power of 8/g. The bacterial manure is mixture of EM bacterial manure and colloid bacillus bacterial manure, wherein the weight ratio of the EM bacterial manure and the conventional tobacco seedling cultivating substrate is 1: 9.0-11.0, and the weight ratio of the colloid bacillus bacterial manure and the conventional tobacco seedling cultivating substrate is 1: 8.8-10.8. The wet tobacco seedling cultivating substrate when being used in a big field with 10-year succession cropping has obvious growth-promoting, yield-increasing and value-adding role for the tobacco. The field experiment proves that the wet tobacco seedling cultivating substrate can shorten the time of reaching to the grant cross period for 6-8 days, increase 10-18 roots in all and improve agronomic character and economical character in the mature period; the leaf area coefficient is increased by 0.43 to 0.64 in comparison with contrast; production value per hectare is increased by about 6000-9000 in comparison with the contrast, and outstanding economic and social benefits are achieved.