Ancient hemp seeds (AHS) and melon seeds (AMS) excavated from the tomb of Marquis Haihun of the Western Han Dynasty (1st century, BCE) had been studied in this research. Elemental analyzer, X-ray fluorescence (XRF) and thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR) was applied in analyzing the samples together with single TG and FT-IR, and contents of different components in the samples had been measured by the Van Soest Method. Analytical results of TG-FTIR analysis showed that evolved gas in the pyrolysis process was mainly consisted of CO2, CO, alkanes, alcohols and phenols, and CO2 occupied a leading role in the gaseous products. Besides, acid detergent lignin of the samples were analyzed by FT-IR, and the analytical results suggested that lignin structures of AHS and AMS were different.