Abstract: Soil is considered to be a gigantic sink and source of chlorinated paraffins. In order to investigate the pollution level and penetration potential of short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) in the Songjiang District agricultural area of Shanghai, the contamination, composition characteristics and potential risks of SCCPs and MCCPs were identified in the surface and core soils (0-15, 15-30, 30-45 cm) by ultrasonic extraction, composite packing column one-step purification coupled and GC-ECNI-LRMS. The results show that: (1) The concentrations of SCCPs and MCCPs in surface soils were 52.58-237.56 and 417.21-1690.82 ng/g dry weight, respectively, and the chlorine content was 58.98%-63.85% and 51.23%-56.50%, respectively. C₁₀Cl_5-7 and C₁₄Cl_6-7 were the predominant congener groups. (2) The concentration of MCCPs decreased significantly with the depth of the soil column (P < 0.01), and the abundance percentages from top to bottom were 60.5%, 25.4% and 14.1%, respectively. The level of SCCP co-ethnic group along the depth of the soil column was relatively uniform, and the level of MCCP co-ethnic group decreased exponentially. The vertical distributions further showed that the shorter carbon chain congener groups with smaller K_ow and higher water solubility tended to penetrate deeper into the soil. (3) Pearson correlation analysis showed that there was not significant correlation between CPs content and TOC content (P>0.05). Principal component analysis showed that the sources of SCCPs and MCCPs were different, which may be related to environmental conditions and the differences in the production process and raw materials of different commercial CPs mixtures. (4) The risk quotient model (RQ) was used to assess the potential risks of SCCPs and MCCPs in the agricultural soils. RQ values for SCCPs and MCCPs in soil were 0.01-0.05 and 0.01-0.06, respectively, indicating that their ecological risks were low (0.01-0.1). The daily exposure level of CPs in children and adults did not exceed the Tolerable Daily Intake (TDI) (10 μg/kg), indicating that there were no risks caused by non-dietary exposure. The studies has shown that the contents of CPs in Songjiang District agricultural area were at a medium level, and SCCPs have strong permeability along the soil column. The biological risk quotient and human health exposure values in this area are low. Therefore, the ecological risks are negligible, but the potential health threat caused by the pollution enrichment of crop should arouse our attention.