This study purposed to look for its uses by analyzing useful substances in kenaf (Hibiscus cannabin us L.) leaves based on the total polyphenol and flavonoid contents in the leaves, DPPH radical scavenging activity of leaf extract, SOD activity, etc. by different growth stage and variety. According to the results of experiment, the total polyphenol content was highest in Everglade-41 (27.9 mg/g dw.), the total flavonoid content was highest in Tainung-2 (42.3 mg/g dw.), and SOD activity was highest in Dowling (96.1 %). However, DPPH radical scavenging activity was similar among the three varieties.