In order to study the pyrolysis characteristic of the heat-not-burn reconstituted tobacco, eight kinds of reconstituted tobacco, three kinds of non-tobacco fiber and tobacco own fiber were tested by TGA (Thermogravimetric Analyzer) technology, and the resulting DTG（Derivative Thermogravimetry）data were analyzed by NRMSE (normalized root mean squared error) to calculate the pyrolysis difference degree. The results showed that the pyrolysis behavior of the reconstituted tobacco used in heat-not-burn cigarettes was much different from that in traditional cigarettes and the pyrolysis difference degree was 37.97%. There was an additional peak in DTG curve of the reconstituted tobacco used in heat-not-burn cigarettes, which can be attribute to the humectants. Compared with the reconstituted tobacco used in traditional cigarettes, the contents of water, extracting solution and lignin were relatively higher, and the contents of hemicellulose and cellulose were obviously lower in the reconstituted tobacco used in heat-not-burn cigarettes.