Abstract: To comprehensively understand the characteristics of odor pollution in an organophosphorus pesticide factory, a retired pesticide factory was chosen as the research object. The odor pollution levels in different regions and media were sensory assessed, the composition characteristics of odorants were compared by analyzing the composition and concentration, and the key odorants were determined by calculating the cumulative odor contribution. Results show that the odor pollution levels of each medium from high to low are production area 1, production area 2, and office area. For the ambient air, the concentration of the total odorants (0.340 9-0.547 9 mg/m³) in the site exceeded the TVOCs concentration in some urban areas and industrial areas, and BTEX, halogenated hydrocarbons, sulfides and oxygenated organic matter are the main components. The key odorants in the production area were ethanethiol, trimethylamine, etc, while the office area were acetaldehyde and dimethyl disulphide. For soil samples, the odorant concentration increased first and then decreased with the increase of the soil layer. The concentration of total odorants in production area 1 was the highest (26.33-60.75 mg/kg), and production area 2 (22.17-49.08 mg/kg), and the office area was the lowest (0.3-1.22 mg/kg). The production area was dominated by BTEX and halogenated hydrocarbons, and the key odorants were dimethyl disulfide, trimethylamine, methylmercaptan, n-butyraldehyde and isobutyraldehyde, etc. The office area was dominated by alkanes and nitrogen-containing organic substances, and the key odorant substances were n-octanaldehyde and n-valeraldehyde, etc.