Abstract: Fusarium oxysporum Schlecht.f.sp.batatas(wollenw.) Snyd.and Hans is the most important disease in Fujian, which affects the yield and quality of sweet potato. The inoculating experiment on the disease fungi of the resistant and sensitive varieties was conducted to study the metabolic characters of phenolics, which include total phenolics,flavonoid,lignin,chlorogenic acid, ferulic acid in plants, and the activity of correlative enzyme of affected sweet potato and the relationship between phenolics and resistance of sweet potato. The results show that resistant ability is related to the accumulation rate and maintenance time of high concentration of phenolics. As the same time, the resistance would be increased with the increase of PAL activity.