Abstract: The change of the parameters plays a great role in Bt fermentation. Bt 8010 was cultured in 5　L fermentor.　Factors including glucose consumption，cell numbers， biomass， spore numbers， dissolved oxygen and pH value were described in detail. The results showed that the concentration of glucose in media had an great effect on the spore numbers.The higher amount of spores(1．28×10¹⁰／mL )was produced in fed batch cultivation than that in batch cultivation. During different growth phases in batch culture ， the size of cells and the oxygen uptake rate (OUR) varied greatly. The highest OUR was observed in exponential growth phase. Therefore， insufficient oxygen supply in exponential phase was probably the main problem in Bt cultivation.