Abstract: Taking BaP(benzoapyrene)and NNK 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone as the target compounds, setting the concentration of cigarette smoke condensate(CSC)at 0(CK), 0.005, 0.010, 0.015, 0.020 mg/mL, that of NNK at 0(CK), 0.005, 0.010, 0.020, 0.040 mg/mL and that of BaP at 0(CK), 0.00025, 0.00050, 0.00075, 0.00100 mg/mL, the synergic mutagenicity of the three components was evaluated. The results showed that: 1)CSC, NNK and BaP all induced mutation of Salmonella typhimurium strain TA98 and TA100 with obvious dose response. 2)There existed obvious synergism between BaP and CSC;high doses of BaP and NNK and low doses of CSC and NNK produced a weak additive effect. 3)Under different conditions, the combined effects induced by the three components on TA98 showed weak additive effect. By and large, the unified mutagenicity of NNK and BaP in the matrix of cigarette smoke showed the complexity of dose-response, time-response and sequence of action.