After Genetic background analysis of Streptomyces diastaticus No. 7 strain M1033, the modified conditions of M1033 protoplasts and transformation were established. Replacement plasmid for homologous recombination was also constructed by inserting tsr gene into glucose isomerase gene. The homologous recombination of GI gene in M1033 chromosomes was achieved by using denatured linearized DNA fragments and glucose isomerase deficient strain M1033LJ was obtained. It is basic for introducing mutation into M1033 chromosome and realizing site-directed molecular reformation.