Abstract: HG-AFS was applied to the determination of arsenic in low alloy steels. Sample was digested with mixed acid of HCl and HNO3, and determined in a medium of HCl (5+95) solution using the mixed solution of 15 g·L-1 KBH4 and 2 g·L-1 KOH as reducing reagent and citric acid as masking reagent. Linear relationship between values of fluorescence intensity and mass concentration of As was found in the range within 60.0 μg·L-1, with detection limit (3s/k) of 0.023 μg·L-1. The proposed method was applied to the analysis of 2 steel CRM′s, giving results in consistency with the standard values. This method was found to be feasible for the determination of trace amount of arsenic (w=0.001%~0.04%) in steel.