Abstract: A vacuum desalting device for iron cultural relics with non-destructive and dynamic monitoring was designed and made, and deionized water was used as the desalting solution. The desalting efficiency was dynamically monitored by the conductivity and chloride content of the desalting solution, and the desalting effect was evaluated by comparing the changes in appearance, quality and surface components of iron cultural relics before and after desalting. The results show that the vacuum desalting method could greatly improve the desalting efficiency, and the dissolved chloride ions were mainly in the free state. The chloride ion concentration in the desalting solution reached 88.11 mg/L after 2 h of desalting, which was 5.32 times that of the soaking desalting method under the same conditions. Under the conditions of this experiment, the total amount of chloride ions dissolved by vacuum desalination method was always greater than that by soaking desalination method. The amount of chloride ion dissolution in the first round of vacuum desalting group was 798.94 mg, which was 3.18 times of that in soaking desalting group. At the same time, the vacuum desalting device not only does not cause additional damage to iron cultural relics, but also can effectively avoid the oxidation of iron cultural relics in the desalting process.