Abstract:Results of two continuous years on the dynamics of residues and degradation showed that the degradation of 2.5% deltamethrin EC and 2.5% lambda-cyhalothrin EC fitted with level dynamics degradation model with the half-life period ranged from 5.28 to 5.73 days and 7.05 to 8.98 days,respectively.30 days after spraying,the amount of residues were 0.012 8 milligram per kilogaram and 0.358 2 milligram per kilogaram.The rate of degradation reached higher than 95%.The residues experiment showed that when 2.5% deltamethrin EC and 2.5% lambda-cyhalothrin EC,2 times and 3 times treatments,after 15 days interval of revovery was recommended,the residues in oriental tobacco were lower than 0.307 8 milligram per kilogram and 0.762 1 milligram per kilogaram,which lower 0.5 milligram per kilogaram and 5 milligram per kilogaram that the maximum residues limit of deltamethrin and lambda-cyhalothrin in tobacco.