Abstract: In order to on-line and real-timely detect the pyrolytic products of tobacco,the thermal decomposition of cut tobacco samples of two different cigarette types were investigated by employing synchrotron photoionization mass spectrometry under different photon energy. The effects of temperature on the products were investigated. The yields of six products, including methane, water, hydrogen cyanide, methanol, acetone and nicotine, of the samples at different temperatures were analyzed and compared emphatically. The results showed that:1)The tobacco pyrolysis products of different ionization energy could be analyzed real-timely by synchrotron photoionization mass spectrometry under different photon enery. 2)The formation of pyrolysis products generally presented the following rules:the yields of methane, hydrogen cyanide, water and acetone increased along with temperature elevation, methanol yield increased initially and then decreased, while nicotine yield gradually decreased. 3)The compositions of tobacco blend obviously affected the yields of pyrolysis products as well.