[Objective] The temporal and spatial distribution characteristics and variation of soil salinity irrigated with magnetized water was explored in order to provide a theoretical basis for the magnetized water irrigation technology of coastal saline-alkali soil.[Methods] The coastal saline-alkali land of a Robinia pseudoacacia plantation in Dongying City was used as the research site to analyze the spatiotemporal distribution and evolution of soil salinity under four measures of freshwater irrigation (FW), magnetized freshwater irrigation (MFW), subsurface shallow brackish water irrigation (GW), and magnetized subsurface shallow brackish water irrigation (MGW).[Results] The two types of magnetized irrigation treatments (MFW and MGW) reduced the soil salinity in the coastal saline-alkali soil. The average salt content of the different irrigation treatments in the different soil layers followed the order:GW > CK(no irrigation) > FW > MGW > MFW and the soil salinity in the different soil layers decreased with an increase of soil depth.[Conclusion] ① Magnetization treatment significantly reduced the soil salt accumulation in the surface soil layer. Especially in the spring and autumn, the use of magnetized water irrigation can inhibit the return of salt to the soil, with the effect being more obvious in the 20-40 cm soil layer. ② Moderate irrigation by magnetizing subsurface shallow brackish water could save water resources for the region and effectively promote soil desalination in saline-alkali soils.