Abstract: 【OBJECT】To study the formation and decomposition of crystal of Bacillus thuringiensis (Bt), and supply theoretics basis for systmic study on its biological characteristic and analysis of its active component. 【METHOD】Bt strain HD-1 was cultured on NA culture media for 24h under 30℃, and then was made into bacterial suspension and observed the formation of crystal with transmission electron microscope (JEM 100-CX-II). Five dissolution methods were used to decompose the crystals of Bt HD-1 and Bt LSZ9408, after that SDS-PAGE was conducted. 【RESULTS】 Bt Hd-1 formed spores and crystals during split process, and the shape of crystal was big diamond. Bt LSZ9408 contained 130 and 65kDa toxic proteins, while Bt HD1 had 130, 65 and 25kDa toxic proteins. 【CONCLUSION】Both of crystals of Bt LSZ9408 and HD-1 contained CryI and CryII type protein toxins.