Abstract: In order to study possible influences on the mainstream smoke hazard index of slim cigarettes by varying cut tobacco structure caused by cutting mode change, four slim cigarettes of two specifications were prepared under different tobacco cutting modes using the same tobacco and auxiliary materials and keeping the other processing parameters and quality indexes the same. The slim cigarette samples made under the conventional cutting mode were marked as the control, and those made under the 40 mm cutting strand length as the test sample. The smoke hazard indexes and combustion states of the four slim cigarettes were analyzed with standard smoke chemistry methods and combustion temperature field analysis. The results showed that: 1) Comparing with the control, the smoke hazard indexes of the two test samples decreased by 10.87% and 6.22%, respectively. In particular, the releases of crotonaldehyde, phenol and HCN decreased by 3%-17%, the releases of ammonia and NNK decreased by 16%-24%, while the releases of benzoapyrene and CO increased slightly. 2) Under the controlled cutting strand length mode, cut tobacco structure was changed, which resulted in the change of the cigarette combustion state, including an increase of heating rate of the combustion cone and the rise of characteristic burning temperature T_0.5, and consequently the releases of the harmful components in slim cigarette smoke.