Abstract: The ‘Y’ -type branch fault, which is widely distributed in Huainan mining area, is more prone to activate water inrush than conventional faults due to its special structural characteristics. In order to reveal the mechanism of water inrush from the floor of ‘Y’ -type branch fault with high confined water in deep mining and put forward the key technical parameters of safe mining, a new type of original rock similar material and a high matching confined water simulation system were developed by taking the floor of No.8 coal face in Liuzhuang Coal Mine as the research object. Based on the self-made similar test platform, a variety of quantitative and qualitative monitoring methods such as digital image correlation method, water pressure sensor, water flow monitoring system and infrared thermal imaging were used. The mechanism of floor water inrush under the synergistic effect of mining disturbance and confined water lifting is simulated. The results show that the new rod and block materials that can be recycled are in good agreement with the confined water system of silica gel water sac, and can simulate the field situation scientifically and reliably. The working face advancing 63 cm is the critical point for the ‘Y’ type branch fault to enter the activation stage. After that, the confined water rises along the main fault to the branch fault, and the water pressure gradually increases. When the working face is advanced to 71 cm, the branch fault of the floor is completely activated, the water inrush occurs in the working face, the water pressure of the main fault is reduced and the water flow is increased. The mining stress has a significant influence on the development of floor cracks. The branch cracks show the law of expansion and development in the vertical direction. When the working face is pushed over 79 cm, the floor cracks gradually close and the water inrush situation is alleviated. Combined with the simulation results and the actual situation of the site, the treatment measures and plans for water inrush from the floor of three ‘Y’ type branch faults are discussed, which provides a certain reference for the study of water prevention and control of similar fault floors.