Abstract: Response of chlorophyll in tobacco leaves on Hg,Cd,Pb stress has been studied by pot experiment in soil-tobacco system.The results show that chlorophyll content and a/b value in tobacco leaves is gradually reduced with increase of Hg,Cd,Pb treatment concentration,whatever it is affected by single one element, two elements or three elements. It is significantly negative correlation between chlorophyll content and concentration of Hg,Cd,Pb.The effect of Hg,Cd,Pb on chlorophyll exists Cd treatment>Pb treatment>Hg treatment,single element treatment