The liquefaction process of cellulose in polyhydric alcohols (PEG 400 and glycerol) was studied by TG-FTIR. Three stages were observed during the solvolysis process and the main liquefaction stage could be further divided into two zones. The differences of liquefaction behavior of cellulose in the two solvents were compared, and the functional groups of volatiles produced by solvolysis were also evaluated. A step-wise procedure based on iso-conversional and Master-plots methods was used for the kinetic and mechanism analysis of the main liquefaction stage. The calculation results based on the kinetic model were in agreement with the experimental data of the conversion rate. The kinetic parameters and mechanism functions between cellulose liquefaction in PEG400 and in glycerol were quite different, which verified that solvolysis behavior and reaction process were seriously influenced by solvent species. Finally, the detailed types of volatiles and product distribution were measured by Py-GC-MS. (C) 2016 Elsevier Ltd. All rights reserved.