In this work, the speciation distribution and availability of selenium in different soils of Shanghai were studied. The results showed that selenium speciation was closely related to the pH and the contents of organic matter in soils, it existed mainly in the elemental, organic and sulfide hound forms, which accounted for 43-60% of the total selenium, secondly in the residue form, which accounted for 23-43%, and the amount of the other forms accounted for only 12-21%.Statistical analysis proved that the soluble, exchangable and carbonate bound forms of selenium were the most available for plants. This suggested that the methods to extrac available selenium by NaHCO₃ or KH₂PO₄ could be used to evaluate the availability of Se in soils.