Abstract: A lignin-based elastomer was prepared by the reactions of polyether polyol and lignin with concentrated sulfuric acid as catalyst. The effects of polyol/lignin mass ratio,polyol combination(mass ration of PEG and PPG),the dosages of catalyst and glycerol,the reaction temperature and the curing time on the mechanical properties of lignin-based elastomers were investigated. The results indicated that the tensile strength of lignin-based elastomers increased with the increases of lignin content,polyether polyol content,sulfuric acid content,the liquefying temperature and the curing time,but the tensile elongation rate reduced. A certain level of glycerol could increase the mechanical strength,but too much glycerol would lead to opposite effect. Through balancing tensile strength and elongation rate,the optimal process conditions of elastomer were polyol/lignin mass ratio 1.8:1,PEG and PPG mass ratio 1:1.2,catalyst content 2%,glycerol content 10%,reaction temperature 120℃ and curing time 10 h. Under these conditions,the tensile strength was 3.64 MPa and the tensile elongation rate was 173%. FT-IR results showed that the mixture of lignin,PEG,PPG and concentrated sulfuric acid did not react without high temperature. And during liquefaction, esterification reaction occurred in the mixture under high temperature. The reaction degree was improved under the condition of high temperature curing,and at the same time the alkylation reaction and condensation reaction occurred.