In order to improve the information intercommunication of water resources systems and the online monitoring capacity of water balance, an intelligent monitoring system for water balance was designed in Balasu Coal Mine, combining the principle of water balance with the Internet of Things, Big Data, and cloud platform technology. Based on the water intake, water use, drainage and water treatment systems, considering the business needs of online water balance analysis, a two-level water balance monitoring system was adopted to build the water resource information monitoring network covering the whole mining area. The water balance intelligent monitoring platform composed of the acquisition, transmission and application layers was constructed using the layered architecture. The hardware design and software design of the system were described. The system could realize the functions such as online monitoring, dynamic analysis, prediction and early warning, report statistics, and visual management of coal mine water balance, so as to improve the management level of comprehensive utilization of coal mine water resources.