Abstract: Analyzes the influence of pyrolytic products in the fire scene on the test results in the case of gasoline arson. The residual components of gasoline in the combustion products were extracted and desorbed.The main components of gasoline were analyzed and detected by gas chromatography- mass spectrometer.The distribution and change rule of components before and after the combustion of gasoline and the interference of common polymer materials in the fire field on gasoline identification were analyzed through combustion test. The results showed that the light components of gasoline decrease and the heavy components increase relatively after combustion. The polymer materials in the fire field mainly produce C9 ~C1 2 straight chain or branched alkanes and benzene series after cracking, while naphthalene series and indene series produce are relatively less. The emphasis of inspection and identification is on extraction, and the difficulty is in result judgment.

Key words: gasoline, combustion residue;automatic thermal desorption, GC/MS, pyrolysis products；fire investigation