Abstract: Taking uredospores of Cronartium ribicola,the Pinus armandii bark infected byCronartium ribicola and the healthy bark as experimental materials,the differences in metabolites extracted with methanol were analyzed by means of UV scanning,TLC and HPLC. The results indicated that the metabolite extracted from uredospores of Cronartium ribicola had two strong absorptive peaks at 214 nm and 307 nm wave lengths,but there were no evident peak values absorbed by the metabolite of tree barks. It was showed by UV scanning at 307 nm wave length that there was a component commonly detected in metabolites extracted from both the infected bark and the uredospores,which was not found out in the metabolite extracted from the healthy bark. Solvent system (ethyl acetate:ethanol=15:1) could differentiate the metabolites extracted from the infected and the healthy barks of Pinus armandii. HPLC detected results also showed that the metabolites extracted from both the uredospores of Cronartium ribicola and the infected bark had similar absorption peak at 214 nm wave length while the retaining time was from 10.30 min to 10.40 min,but the metabolite extracted from the healthy bark did not have this special peak. The above resulted showed the possibility of telling the difference of the infected plants from the healthy ones.