Abstract: To achieve comprehensive utilization of different biomass resources in classification, the low temperature pyrolysis characteristics of corn cob and eucalyptus were investigated by means of thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Experimental results showed that the pyrolysis products at low temperature were significantly different for different kinds of biomass materials. The degradation of corn cob mainly generated acetic acid, 1-hydroxy-propanone, 2,3-dihydro-benzofuran and 2-methoxy-4-ethenyl-phenol. While acetic acid, furfural and 5,6-dihydro- 4-hydroxy-2H- pyran-2-one were associated with the degradation of eucalyptus. The species in the pyrolsis products of biomass at low temperature were found to be less, and distributed in a relatively narrow temperature range. The contents of acid and furan products from pyrolysis of corn con and eucalyptus, and pyrans from eucalyptus were decreased with pyrolysis temperature increasing. The hemicellulose in biomass was effectively decomposed by low temperature pyrolysis, which could provide theoretical guidance for decreasing acidity and water of bio-oil by pyrolysis at medium temperatures.