Abstract: A luminol-ClO－ chemiluminescence（CL）method for the determination of available nitrogen in soil with high sensitivity was developed. It was found that NH4+ could reduce ClO－ in the base solution. A new sensitive and selective CL method for the determination NH4+ in the dry soil was found based on the reductive reaction. The linear-response range of the method was 0.01~1.50mg/kg with a linear correlation coefficient of–0.9989.The detection limit was 1×10-3mg/kg. The RSD was less than 2.7%(n=5). The recovery of the method was 85.8%~94.5%. The method was applied to the detection of available nitrogen in soil samples with satisfactory results.