Abstract: Objective To explore induced addicton of cigarettes smoke by psaaive smoking and its influence on body weight and inmunity in mice.Methods Thirty 2-month-old male Kunming micew ere chosen and divided in to the control group breathing the natural air and the passive smoking group.The passive smoking group was exposed to a sealing box filled with cigarettes smoke from a stick of cigarette partly burning The process lasting for 40 mmutes was perfouned Nvice a day Comparatively,the control group was exposed into the same size sealing boxfilled with natural air.The conditioned place preference (CPP) was used to test the addiction to cigarettes smoke To test the influence of the addiction on themor phological development and inmunity,the body weight,indexes of spleen and thymus gland,the content of C₃,C₄ and IgA,IgG,IgM in the peripheral seiwn were detected and analyzed,and the inmunoturbidinetry(ITM)method was used.Results For the results of CPP,there was no statistical significance between control group and the passive smoking 4w group (P>0.05),while there were statistical significances between the control group,the passive smoking 4w group and the passive smoking 8w group(P<0.01;P<0.05).The addiction and the withdrawal perfounances were observed The body wBights and the weight grow th rate of the passive smoking groups were less than that of the control group(P<0.01).The index of spleen,the contents of C₃,C₄ and IgA,IgG of the passive smoking groups were less than that of the control group (all P<0.05 except C₃ P<0.01) Conclusion The addiction could be induced by long-teen cigarettes smoke exposure and the moiphological development was retarded and inmunity was weakened in passive sm oking Kunming mice