Polyolefin resin is affected by raw materials, processing technology and various auxiliaries in processing process, and the produced polyolefin resins will release volatile organic compounds to different degrees, causing pollution to the environment and harm to human health. In this study, the polyolefin resin products, resin raw materials and additives used in processing were used as experimental materials, and one-dimensional chromatography technology (GC/MS combined with gas chromatography and mass spectrometry) and full two-dimensional chromatography technology (two-dimensional gas chromatography and time-of-flight mass spectrometry GC×GC-TOF/MS) were used to systematically characterize volatile organic compounds of polyolefin resin. The molecular sensory evaluation technique was used to screen odor-contributing compounds and reveal their chemical nature. The results show that 123 volatile compounds in 2 kinds of resin products, 109 volatile compounds in 2 kinds of auxiliaries, 57 volatile compounds in 1 kind of raw material were detected by GC/MS, a total of 159 volatile organic compounds. A total of 222 volatile compounds were detected by GC×GC-TOF/MS technology, which could be divided into 149 kinds. Compared with one-dimensional chromatography technology, the number of compounds is 99 more and the types of compounds are 43 more. A total of 278 volatile compounds were detected by the two techniques, and 36 odor compounds were screened by molecular sensory evaluation. The main odor contributing substances are 4-methyloctane, toluene, o-xylene, nonylaldehyde, capric aldehyde and 2-ethyl-1-hexanol.