Abstract: Brown spot needle blight(lecanosticta acicola) is an important disease on slash pine and loblloly pine in south China. This study analyzed needle peroxidase and polyphenol oxidase activities of 9 resistant clones and 4 susceptible individuals.The results showed in healthy needles the peroxidase activities were very high and the polyphenol oxidase activities were relstively lower.Moreover,the two enzymes in resistant needles were of obvious higher activies than in susceptible needles.There existed a positive relation between peroxidase and polyphenol oxidase activities,the relation coefficient being up to 0.9.After resistant and susceptible needles were treated with primary toxin of brown spot fungus,the peroxidase activities all increased, but, the increase extent between resistant and susceptible needles did’ not show much difference.On the other hand, polyphenol oxidase activities all reduced after treated. and the reduction extent of resistant needles was greater than susceptible needles.