The invention relates to a preparation process of a live 
bacillus thuringiensis preparation. The preparation process comprises the steps that 
bacillus thuringiensis is inoculated into a 
fermentation medium to be cultured after being subjected to primary and secondary seed enlarge culture; the quantity and conversion rate of bacillus are increased through fed-batch of a 
carbon source in the 
fermentation process, thus obviously increasing the unit yield and reducing the 
unit cost; after 
fermentation is completed, the fermentation liquor is concentrated by using a vacuum film 
concentrator and the soluble synergistic substances, growth-stimulated substances and bacteriostatic active substances in the fermentation liquor can be effectively recovered; the concentrated fermentation liquor is dried and granulated by multistage low temperature spray fluidized 
drying equipment, the granules are sorted and the 
fine powder is trapped by a 
cyclone separator and returns to be re-granulated, thus obtaining the 
bacillus thuringiensis product, wherein, through biological 
assay, the activity of each 
gram of the bacillus thuringiensis 
powder on cotton bollworms is not lower than 80000IU / mg and the content of 
insecticidal crystal proteins in the product is not lower than 13%; the 
tail gas is treated and is discharged up to the standard. The preparation process has the advantages that the active substances in the fermentation liquor can be furthest retained; the product quality and the equipment 
utilization rate are high; the 
biological activity is better maintained; the 
waste gas and the 
wastewater are discharged up to the standard; the preparation process can be used for large-scale industrial production.