The invention discloses a CRISPR Cas9 system for Bacillus subtilis genome edition and an establishment method thereof, belonging to the technical field of gene engineering. A knock-out plasmid PHY300dsrf is established; and the plasmid comprises sgRNA and cas9 genes of the specific targeted target gene, a homologous restoration arm, and replication initial points and tolerance screening markers of Escherichia coli and Bacillus subtilis. The sgRNA of the specific targeted srfA-C gene can guide the cas9 protein to cut double strands at the specific site of the srfA-C gene, and can be used for accurate homologous recombination on the genome under the guide of the homologous restoration arm, thereby introducing the XhoI enzyme digestion site at the rupture. When the tank feed fermentation culture is carried out on the Bacillus subtilis of which the srfA-C gene is successfully knocked out, the foam is obviously reduced, which proves that the CRISPR/Cas9 gene editing system can effectively perform gene edition on the Bacillus subtilis genome.