Controlling automatic water addition in the sintering process plays a key role in stabilizing the "water" in such three elements as "wind, water and carbon" in the sintering process. By studying the influence of batching quantity, material properties, flow rate and detection method on the moisture control of the mixture, the difficulties and key points on controlling automatic water addition are analyzed systematically, and countermeasures are proposed. In the actual solution, the influence of the moisture measurement values of the first and second mixtures, as well as the fluctuations of the typical hydrophilic and hydrophobic materials and the amount of dust removal ash material, on the moisture control are considered, and the multi-variable fusion control algorithm is used to automatically control the water addition. A safety and error-proof design is carried out to avoid the risk of "running dry material and thin material" caused by abnormal equipment and control parameters, and to improve the reliability of the production system. The actual operation data shows that the stability of moisture and the utilization coefficient of the sintering machine have been significantly improved after the implementation of the above automatic water addition system.