Abstract: Objective To investigate the effects of smoking on pulmonary function and urinary concentrations of polycyclic aromatic hydrocarbon (PAH) metabolites among male adults in Guangzhou.Methods A systematic sampling method was employed to select male adults in Huangpu District and Zengcheng during July 2012. All subjects were aged 45 years and over, lived in the location more than half year, and interviewed with the questionnaire. Ten OH-PAHs in urine and pulmonary functions were tested. Covariance and multiple linear regression analyses were employed to test relationships between smoking, pulmonary functions and OH-PAH concentrations.Results A total of 142 male adults were recruited whose average age was (61.30±9.73) years. Ninety four of them were smokers (66.20%). The covariance analyses revealed that the FEV1/FVC (F=6.84), FEF25-75 (F=5.52) and MVV (F=4.54) were lower in smokers than those in none-smokers (P<0.05 for all). Smokers had higher concentrations of urinary 1-OHNa (F=10.21), 2-OHNa(F=8.74）and 2-+3-OHFlu (F=4.11) than none-smokers (P<0.05 or P<0.01). Furthermore, 2-OHPhe (β=-6.34), 3-OHPhe (β=-6.39), 4-OHPhe (β=-5.44), and 1-OHP (β=-5.03) had negative relationships with PEF (P<0.05 for all); 2-OHNa had negative relationship with FEF25-75 (β=-5.91, P<0.05); 1-OHNa (β=-2.85) and 2-OHNa (β=-3.11) had significantly negative relationships with MVV (P<0.05 for all). Conclusion Smoking could reduce pulmonary functions of male adults in Guangzhou and increase their internal exposure to PAHs. The internal increase in PAHs was related to the declined pulmonary functions.