The invention discloses a system and method for blocking bottom plate cracks through air-entrapping silicification. The system comprises a sealing device, a water glass supply device, a carbon dioxide supply device and a cleaning device. The sealing device comprises a sealing ring and a flange. A main pipeline is vertically arranged at a drill hole. The part between the main pipeline and the drill hole wall are sealed through the sealing ring. Two branch pipelines including the first branch pipeline and the second branch pipeline are arranged on the top of the main pipeline, the first branch pipeline is connected with the water glass supply device, and the second branch pipeline and the carbon dioxide supply device are connected. The water glass supply device is used for supplying Na2SiO3, the carbon dioxide supply device is used for supplying CO2, and therefore crack blocking can be achieved. The cleaning device is used for washing water glass left after water crack blocking after locking is ended. By means of the system and method, the bottom plate fine cracks can be effectively blocked, confined water is prevented from entering a mine, and good application and popularization value is achieved.