Abstract: To study the influences of linear and rotary smoking machines on the determining results of total particulate matter(TPM) and seven chemical components, CO, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone(NNK), benzoapyrene(BaP), crotonaldehyde, phenol, hydrogen cyanide(HCN) and ammonia(NH₃), in mainstream cigarette smoke, nine Virginia and eleven American blended cigarettes of different tar yields(1.0-13.3 mg/cig) weretested, and the effects of the two smoking machine types on the test results were investigated under ISO and health Canada intense(HCI) smoking regimes. The results showed that: 1) The test results obtained by the two type smoking machines were more consistent under ISO smoking regime, notably, the results of TPM, crotonaldehyde and HCN differed greatly under HCI smoking regime. 2) Under the two smoking regimes, the correlations between standard deviations(n=5) and mean values for NNK, BaP and phenol were generally closer than those for CO, crotonaldehyde, HCN and NH₃; however those for the said seven components were closer under ISO regime than under HCI regime. 3) The precision differences between linear and rotary smoking machines were basically the same, namely in most cases, the average coefficients of variation(CV) tested by linear smoking machine, in five repeated experiments of 20 samples with different smoke yields, were higher.