In order to know the resource, preservation and development of lignin, a useful biomarker of SOM (soil organic matter), samples of lignin extracted from the buried ancient paddy soil at Chuodun ruin site, China were analyzed with the CuO oxidation method for its characteristics and catabolites of phenolic acids. The buried ancient paddy soils was identified to be more than 6 000 years old and confirmed with the archaeological method. Results showed that the total lignin-derived phenols in that soil ranged from 0.004 to 0.035 mg kg^-1, decreasing with the depth and was obviously lower than those in the modern paddy soils (0.27～0.34 mg kg^-1), but no significant difference was found between buried paddy soils that had been planted with rice or without rice. The composition of oxidized phenols in the soil with S-to-V and C-to-V ratios being 0.40～1.55 and 0.15～0.89, respectively, demonstrates that non-woody angiosperms once grew in the soil; between ancient soils with rice or without rice, no significantl difference was found in S-to-V and C-to-V, suggesting that it is not easy to distinguish origin of organic matter of the same kind in the buried soils based on characteristics of lignin. Lignin carbon accounted only for a small portion of the SOC in buried ancient paddy soils, indicating lignin is not so preservable as usually expected in the soil.