In order to reveal the deposition regularities of calcium carbonate in the crack and improve the sealing efficiency, ten groups of grouting tests under gravity in concrete split cracks were conducted. The test parameters included different volumes of bacterial liquid, whether the bottom pasted bacteria liquid filtered layer(medical cotton) at the bottom of the crack, or the bacterial fixation liquid is poured into the crack before grouting. The results show that the more bacterial liquid poured into the crack, the more efficient it is for repairing cracks. The calcium carbonate is firstly formed at the bottom of the crack in the specimen which has the bacterial liquid filter layer at the bottom of the crack and calcium carbonate is firstly formed in the middle and lower part of the crack in the specimen which has no bacterial liquid filter layer. The specimen filled with the bacterial fixation liquid before grouting has more repairing efficiency than the specimen that is not filled. With the increase of grouting cycles and depths of crack, the thickness of calcium carbonate in crack inner wall is increased. Calcium carbonate is more likely deposited in the rough, high vertical inclination and roundabout internal wall of the crack.