Two representative herbaceous plants, namely, rice straw and bamboo, were selected as the materials to produce two kinds of enzymatic/mild acidolysis lignin （EMAL） by isolating lignin via an enzymatic/mild acidolysis process. Then, the chemical structure and properties of the products were characterized by means of elemental analysis, FT-IR and quantitative 31p-NMR, and the pyrolysis characteristics of the products were investigated by means of TG-FTIR and Py-GC/MS. The results show that （ 1 ） rice straw contains more pentosan and extractives while bamboo contains more cellulose and lignin; （2） guaiacyl units （G type） are abundant in rice straw EMAL while bamboo EMAL possesses more syringyl units （S type） ; （3） during the thermal degradation, there is one distinct weight loss peak at 384℃ in bamboo EMAL but two at 270℃ and 384℃ in rice straw EMAL;and （4） the difference in chemical structure greatly affects thermal decomposition behaviors as well as pyrolysis products of EMAL.