The present paper deals with soil secondary alkalization due to irrigation with alkaline groundwater of low salinity.It was showed by modelling experiment of soil column in laboratory that the accumutation of soda,pH and ESP of soil increased due to irrigation of the soil with alkaline groundwater of low salinity.The degree of soil alkalization depended on the content of residual sodium carbonate in alkaline groundwater of low salinity and the time of irrigation.henerally speaking,the higher content of residual sodium carbonate in groundwater,the more soil alkalization is.At the same time,the thickness of soil alkalized horizon was increased with the increase of irrigation time.