Soil available nitrogen of Picea crassifolia forest in the eastern Qilian Mountains was studied through field sampling and laboratory analysis.The results showed that:(1)soil total available nitrogen(NH₄⁺—N and NO₃^-—N)in 0—40 cm of Picea crassifolia forest was 17.26～20.76mg/kg,NH₄⁺—N was the major existing forms of soil available nitrogen with content exceeding 66.72 %;(2)Soil NH₄⁺—N decreased with the increasing soil depth,and nosignificant change of NO₃^-—N occurred,but NO₃^-—N was more sensitive to soil microenvironment factor compared with NH₄^-—N ;(3)The correlation between soil NH₄⁺—N and organic matter was significant(p<0.05),while the relation between soil NO₃^-—N and organic matter was not significant.NH₄⁺—N as the main forms of soil available nitrogen largely depended on the soil neutral pH,low temperature and high moisture content in the research area.