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.