Abstract: The types and the quantities of monosaccharide consisted in the six different plant cell walls were determined by the ion chromatograph in this experiment. And the ruminal fermentable characterization and the relative contribution to the methane yield in ruminant animals were compared with the six different plant cell walls by incubating them with the ruminal fluid as the method of gas production (Menke and Steingass, 1988). The gas production in 72 h, the maximum gas production, the rate and the lag time of gas production differed greatly among different plant cell walls (P value were <0.000 1, <0.000 1, 0.007 3 and 0.000 2, respectively). The percentage of methane and the carbon dioxide in the gas compostion differed significantly (P<0.000 1). The activities of CMCase and Avicelase in the fermented fluid had no remarkable difference (P=0.531 6 and 0.506 3, respectively) but the xylanase activities were different greatly (P=0.017 9). The total volatile fatty acid, the molar percentage of each kind of volatile fatty acid except butyrate (P=0.468 0) were different significantly (P<0.055). It was concluded that the types and the quantities of monosaccharide consist in the six different plant cell walls and their ruminal fermentable characterization and the relative contribution to the methane yield in ruminant differed greatly.