Cry1Ac protein is known as one of toxin crystal proteins synthesized from Bacillus thuringenesis that plays a critical role for the insect resistance. Recently, cry1Ac genes have introduced into many plants in general and soybean as well. However, the gene expression of cry1Ac genes in transgenic plants remains low that need to be improved. Several mutations we reintroduced into the cry1Ac genes in order to enhance the insecticidal effect. In this study, the cry1Ac with mutant #2, #11 and #16 were transformed into Kwangan, a Korean soybean variety by using the “half-seed” method. The plant lets carrying modified cry1Ac genes were primarily selected on media containing Phosphinothricine (PPT), a bar selective agent and Basta leaf painting. Then, the presence of introduced genes in T0 plants and the gene expression were investigated by PCR, RT-PCR and Real-time PCR. PCR and RT-PCR analysis showed expression of bar and cry1Ac genes from tested transgenic soybean plants. The number of copy of bar gene ranged from 1 to 3 by Real-time PCR analysis. These results provided a fundamental back ground for our further experiments: Confirmation of the gene expression by Southern blot and identification of the function of modified cry1Ac by insect bioessays.