Abstract: B. thuringiensis(Bt) is a very important entomopathogen since it can produce specifically toxic crystal proteins against many agriculturally and biomedically detrimental pests including lepidopteran, dipteran, coleopteran, hymenopteran, acarian and nematodes. Commercial Bt-based biopesticides were used worldwide for controlling economically important pests in the past 30 years. Significant progress has been made in recent years on Bt genetics, molecular biology and genetic engineering. This review will focus on classification and insecticide mechanism of Bt crystal protein genes, the application of Bt crystal protein genes in engineering of insect-resistant plants. In addition, the potential problems of Bt toxic protein gene engineering and resolving ways will be discussed.