The invention discloses an intelligent irrigation regulation and control system and method based on dynamic water content estimation. The system comprises a wireless monitoring system, an irrigation decision making system and an irrigation control system. The wireless monitoring system comprises a plurality of monitoring sub-systems, and each monitoring sub-system comprises a monitoring communication unit and a soil water detecting unit. The irrigation decision making system comprises a decision making communication unit, a decision making processing unit and a decision making power management unit. The irrigation control system comprises a plurality of irrigation sub-systems. The method includes the steps that the soil moisture detecting unit detects environmental data of soil in real time, the monitoring communication unit regularly acquires data of the soil moisture detecting unit, the decision making processing system acquires data received by the decision making communication unit, the overall water content of an irrigation area is estimated, control data are generated, an electromagnetic valve can generate a corresponding action, and autonomous irrigation is performed. According to the system and method, the water content of the whole irrigation area is dynamically estimated through a maximum likelihood estimation method, the soil water content is estimated more accurately, and accurate regulated and controlled irrigation is achieved.