The research of irrigation regulation and storage engineering on groundwater salinity was investigated in reclaimed water irrigation district (RWID) of Beijing for site selection. Five research wells with different depths around regulation and storage engineering were drilled to monitor water quality changes. Chloride ion of leachate, total nitrogen, total phosphors, hardness of water samples increased, and removal rate of total nitrogen, total phosphorus of water samples decreased by 97.3% and 99.0%, respectively in 12-meter vadose zone after infiltration, and the measured parameters were close to groundwater background values. Measured results indicated that groundwater was not polluted by reclaimed water infiltration, and there was no significant difference between the effect of reclaimed water and other water resources infiltration on groundwater. The vadose comprising of loam, sand and clay can prevent groundwater pollution for site selection of regulation and storage engineering in RWID.