Step-wise pyrolysis of fir was conducted in the presence of catalysts by using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The effects of catalysts and temperature on composition and content of the pyrolysis products were studied. The results showed that few types of the products were found in the first-step 300℃ pyrolysis and the main products were extractives, while a great variety of products were detected in the second-step 500℃ pyrolysis. ZSM-5 and MCM-41 could reduce the contents of carbonyls and macromolecular lignin derivatives. ZSM-5 catalyst was helpful to reduce the content of acetic acid, and produced lots of aromatic hydrocarbons in the pyrolysis products. The content of acetic acid and furfural in the prolysis products were obviously increased by the presence of MCM-41 catalyst. 