The pyrolysis behavior of pelargonic acid vanllylamide(PAVA) was investigated by gas chromatography-mass spectmmetry with on line pyrolysis(Py/GC-MS) in the presence of helium.The influence factors of PAVA pyrolysis behavior such as different temperatures and different time were studied.GC-MS was used for the qualitative and semi quantitative analyses on PAVA pyrolysis products.The results indicated that pyrolysis temperature had a significant effect on the types and relative contents of pyrolysis products.14 products were detected when the temperature reached 700 ℃ above,including nonanamide,2 methoxy 4 methylphenol,1 hexene,nonanenitrile,nonaldehyde,etc.The pyrolysis rate of PAVA increased gradually with time increasing.According to the pyrolysis products and their contents,the pyrolysis regulation for PAVA was preliminarily dicussed.