Abstract: Volatile oils from celery seeds were extracted by SFE-CO2 technique.And its chemical constituents were identified by GC-MS.36 constituents were separated from volatile of celery seeds.And 27 compounds were identified which accounts for 99.72%, the content of limonene in the volatile oil of celery seed was the highest (33.08%) , the other chemical constituents were acetamide, N, N'-1, 2-phenyleneb (23.04%) , γ-elemene (14.96%) , 1-propanone, 2-chloro-1- (2, 5-dimethylphenyl) -2-methyl- (6.01%) , N, N'-diacetyl-1, 4-phenylenediamine (5.73%) , caryophyllene (3.51%) , The removal rate of essential oil of celery seed on sodium nitrite was calculated by ultraviolet spectrophotometer.Results showed that the volatile oils of celery seeds were able to scavenge sodium nitrite efficiently.Maximum removal rate was 89.80%, when the amount of volatile oils was 40μL.