Small cracks in concrete turn into large cracks and lead to a shorter useful life of concrete structures,over time.Therefore, the speed of the growth of the cracks should be limited.crack healing in concrete is one of the effective ways to prevent the spreading of cracks.For this purpose, various methods for repairing cracks on concrete have been investigated and compared with others.This research presents a biological method for improving the self-healing of concrete beams by microbial activity of Bacillus subtitles bacteria.In this study, healing was done by injection of Bacillus bacteria through the insulin syringe into the cracks.For this purpose, 6 concrete beams with dimensions of 15 × 15 × 120 cm were constructed and the self-restraint property was investigated and evaluated by making cracks by torsional static load.finally, it was concluded that base on the final torsion moment of the beams. The beam which repaired, increased the torsional capacity of the original control sample by 93.13% and also increased the torsion strength of the cracked beam by 7.6 times.