Laboratory and greenhouse experiments were condu ted to study thte forms of selenium and the extraction of available selenium in several soils of Shannxi. Based upon the procedure of fractionation of phosphate proposed by Chang-Jackson, the forms of inorganic soil selenium were divided into three fraction—NH₄Cl-Se, Al-Se, and Fe-Se. The sum of these fractions accounted for 37-65% of total content of soil Se with an average of 48%. There was a significant correlation between the content of total Se and NaHCO₃ soluble}e and the three fractions, but no significant correlation between it and the water soluble-Se. The date obtained from the greenhouse experiment revealed that in the case of calcareous soil investigated, NaHCO₃ soluble-Se was very consistent with the plant Se uptake. There was, however, no significant correlation between H₂O soluble-Se and the plant Se uptake. This suggests that the extraction method of soil available Se with NaHCO₃ can be used to evaluate the availability of Se in calcareous soil. But the H₂O soluble-Se can not be used to estimate the possibility of Se to be taken up by plants.