The low-tempeature thermo-chemical convesion processfor sewage sludge is a prospective technology. Through which the energy in the sludge can be recowered, with the help of elementary analysis of sewage sludge and its conversion products. Thermal gravimetric analysis (TGA)of the sludge and GC/MS analysis of the darivadoil, a study was carried out on element transfer, charactersite conversion temperature and conversion reaction mechanism of the process. The following resuits are obtained; 1) the predominant convesion reactions are distillation of aliphtatic compounds, splitting of protein peptide bonds and group transfer, and 2) the main components involved in the conversion are aliphatic compounds and protein, with the lower reaction temperature for the former, the higherf or the latter and the highest for saccharides, Based on the emchanism analyses, the simplified reaction model of the thermo-chemical conversion process for sewage sludge consists of two sorial competitive reactions (producing volatile reatter and char respectively), The estimated Amtermius Kineticparametars of the reaction model bsased on TGA testing results are A1=4.15