Abstract: In order to study the influences of two smoking regimesISO and Health Canadian Intense (HCI) smoking regimes on the precision of specific measurements and results of mainstream cigarette smoke, a series of collaborative studies were carried out using seventeen smoke analyte indices including, puff number, total particulate matter,tar, nicotine, carbon monoxide(CO); N-nitrosonornicotine (NNN), 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone(NNK); benzoapyrene (BaP); formaldehyde, acetaldehyde, acrolein, crotonaldehyde; phenol; hydrogen cyanide (HCN); ammonia; 1,3-butadiene, benzene. The results were statistically analyzed, the repeatability (r) and reproducibility (R) of nine methods at six delivery levels (m) were obtained according to GB/T 6379.2-2004/ISO 5725-2:1994 recommendations, and the linear regressions of m with r and R for each analyte were determined. The results showed that:the relative repeatability (r%) and relative reproducibility (R%) for tar, nicotine, CO were about 10% and 20%, respectively, while those for the other analytes were between 20% and 45%. The precision for tar, nicotine, CO under both repeatability and reproducibility conditions were clearly better than that for the other analytes. In addition, no significant improvements for measurement precisions were found under HCI smoking regime even though the analytes'yields were much higher than those under ISO regime. In contrast to the samples smoked under ISO regime, a much weaker correlations of linearity between m and r or R were obvious for most of the analytes under HCI regime. Meanwhile for some analytes, the measurement differences between the two type (rotary and linear) smoking machines were higher under HCI regime. Following the existing mainstream cigarette smoke collection, the stability of smoking machine's puffing parameters, such as puff number, were lower under HCI regime. These results indicated that the typical smoking machines are not optimised for the robust analysis of mainstream cigarette smoke under HCI smoking regime.