Abstract: The petrochemical industry is one of the key targets of complaints, however, its odor pollution level, characteristics and cause are not clear. To address the problem, the portable electronic nose equipment independently developed with migration and mass spectrometry technology was used to establish a peculiar odor navigation monitoring system. The large petrochemical enterprise in Tianjin was investigated and analyzed by emission characteristics using this system and laboratory analysis methods. In addition, the key points and regional component spectra were established. The fingerprint was drawn by using theoretical odor concentration and gas chromatography-olfactometry analysis methods. Results show that the odor concentration levels of 10-1 100 were tested by electronic nose equipment, a total of 14 odor incidents were found, oxygenated compounds, nitrogenous compounds, alkane and alkene were the main odorants, and the key pollution areas were determined including the installation area, sewage treatment area and hazardous waste storage area. The odor concentrations in 4 processes exceeded the standard of Emission Standards for Odor Pollutants (DB12/059—2018). A total of 262 substances were detected in stack and fugitive emissions, of which aromatic hydrocarbons, ketones, sulfides, alkanes and alkenes were the main detected substances, and the total concentrations of stack and fugitive gas in sewage treatment were the highest, reaching 22.868 8 mg/m³ and 16.321 3 mg/m³, respectively. There were 37 substances selected for the source profile including sulfides, oxygenated organic compounds, alkanes, alkenes, aromatic hydrocarbons and halogenated hydrocarbons based on the concentration and detection rate. The fingerprint index substances included sulfur dioxide, dimethyl disulfide, acetaldehyde, acetic acid, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, indene and 1-methyl-1H-indene.