Abstract: In order to evaluate the level and distribution characteristics of Dechlorane Plus(DP) in the atmosphere of Huai'an City, 96 atmospheric samples were collected using atmospheric passive sampling method from 2016 to 2018. The ρ(DP), ρ(syn-DP), and ρ(anti-DP) were analyzed, and the mass fraction of syn-DP isomers(f_syn) was combined to trace the migration and transformation of DP in the atmosphere. The result showed that:(1) DP was detected in all samples. The range of ρ(DP) in the atmosphere was 1925-4221 pg/m³, with an average of 3053 pg/m³. In addition to the sampling sites in the plant, the range of ρ(DP) in the atmosphere at other sampling sites was 9-92 pg/m³, with an average of 42 pg/m³.(2) The highest value of ρ(DP) appeared in the plant, and its ρ(DP) was about three orders of magnitude higher than the sampling sites outside the plant.(3) The distribution of ρ(DP) in the atmosphere was related to the seasons, showing the characteristics of high in winter and low in summer.(4) The average f_syn value at the sampling points in the plant area was 0.26, and the average f_syn value at the sampling point outside the plant area was ranged from 0.18 to 0.53, with an average of 0.28, which was equivalent to the average f_syn value of the sampling points in the plant area. This study showed that the high levels of DP in the atmosphere of Huai'an City mainly came from the production of DP, and the f_syn values of syn-DP and anti-DP demonstrated seasonal and spatial variations.