Salt in greenhouse soils was studied in Shouguang,Shandong Province.The results indicate that 1) the salt content in greenhouse soils was much higher than that in open field soils,with an average value being 2.69 g kg^-1(CV=58%) and only 0.61 g kg^-1(CV=14%),respectively,in 0～20 cm soil layer;2) the salt content in greenhouse soils might reach the threshold value for normal growth of crops after 4 years of cultivation,and secondary salinization of the soil is a main limiting factor for sustainable development of greenhouse cropping;3) apart from HCO₃^-,the contents of NO₃^-,SO₄^2-,Cl^-,Ca²⁺,Mg²⁺,K⁺,Na⁺ increased significantly in greenhouse soils,and Ca²⁺and NO₃^- were the majorions in the soils,accounting for 47.4% and 19.3% of the total salt in the topsoil,respectively;and 4) compared with neighboring open field soils,greenhouse soils displayed apparent phenomena of salts leaching downwards to the bottom of the soil(80～100 cm) and salts accumulating in the topsoil(0～20 cm),especially NO₃^- that has seriously affected quality of the groundwater in the area.