OBJECTIVE： To provide reference for the identification， processing， processing technology and research for thermal decomposition products. METHODS： Thermogravimetry - derivative thermogravimetry （TG-DTG） and differential thermal-derivative differential thermal （DTA-DDTA） analysis were conducted to scan thermal spectrum of tripterygium from 3 places and T. hypoglaucum， T. regelii， common counterfeits Actinidia arguta and Vitis quinquangularis， determine 7 medicinal materials， its dregs and extractum， and analyze differential spectrum of T. wilfordii and dregs. RESULTS： The TG-DTG and DTA-DDTA thermal spectrum were not only basically similar to each other but also to their dregs. There was a singlet main characteristics peak at about（299±3）℃ only in the DTG curves of extracts of tripterygium from 3 places and T. hypoglaucum extractum with similar intensity， while T. regelii， counterfeits A. arguta and V. quinquangularis showed multiple peaks， and （299±3）℃ was not the main peak. CONCLUSIONS： The thermal spectrum can not distinguish tripterygium and its counterfeits； extractum DTG curves can do it； suitable processing temperature of tripterygium was 200-380 ℃. The study can provide reference for the identification， processing， processing technology and research for thermal decomposition products.