Abstract: The dynamics of the soil salinity and moisture on saline and alkaline land of seabearch after plantation in Hangzhou bay were determined and analysed.The results showed that the difference in soil average salinity contents of 0～80 cm soil from May to November among 4 plantation land models(standⅠwas mixed forest of Vitex trifolia L.var.simplicifolia Cham.and Ligustrum lucidum Ait.in spring in 2003,standⅡwas Morus alba L.pure forest in spring in 2003,stand Ⅲ was tree species contrast forest in spring in 2004,stand Ⅳ was mixed forest of Alnus cremastogyne Burkill.,Morus alba L.and Cinnamomum porrectum(Roxb.) K.in spring in 2004) and no plantation land(CK) were significant,the average soil salinity contents of 2 plantation land models established in spring in 2003 were 0.101% and 0.196%,the average soil salinity contents of 2 plantation land models established in spring in 2004 were 0.349% and 0.425%,but the average soil salinity contents in no plantation land was 0.466%.The change extent of average soil salinity contents of 4 plantation land models were not obvious in 7 months,but the change extent in no plantation land was obvious.The plumb distributing rule of soil salinity contents,the soil salinity contents were increase along with soil deepness adding in plantation land,but that were reduce along with soil deepness adding in no plantation land.The change trend of soil salinity contents in surface layer soil were evident along with month change among plantation land and no plantation land,but that were nearer in under layer soil.The change trend of month average soil moisture contents were nearer among plantation land and no plantation land,the soil moisture contents were increase along with soil deepness adding,the cover with degree of earth's surface were higher,the increase breadth were delayer