The characteristics of Spartina alterniflora residue after producing methane (SAR) digested alone and co-digestion of various proportions of chicken manure and SAR were investigated by batch model at 35 degrees C +/- 1 degrees C. The initial total solid (TS) loading of all treatments was 8.0%. The results indicated that there was still some biogas produced by SAR with TS biogas yield of 107.25 mL x g(-1) and average methane content of 76.92%. The cellulose crystallinity of re-digested SAR was destructed by anaerobic microorganisms, and the destruction rate was 5.55%. Co-digestion meliorated the environment where microorganisms lived in and increased the cumulative biogas yield. When the ratio of chicken manure to SAR was 4 : 1, the cumulative biogas yield was highest while the cumulative biogas yield of T1 (the rate of chicken manure to SAR is 5 : 0 based on TS), T3-T6 (the rate of chicken manure to SAR are 3 : 2, 2 : 3, 1 :4 and 0 : 5 based on TS, respectively) were 61.31%, 62.09%, 52.15%, 39.74% and 31.67% of it. The anaerobic fermentation type of co-digestion is mix acid type fermentation. Co-digested with chicken manure promoted the destruction of cellulous crystallinity by 1.13% - 21.61% and especially when the rate of chicken manure to SAR was 4 : 1.