In this study, we selected some material to have potential bioactivity from natural plants, confirmed as basic data for industrializing and tried to develope the food materials using them. DPPH, ABTS, antioxidant protection factor, TBARs and antimicrobial activity of extracts from Rosa multiflora Thunberg fruits were determined. The total phenolics extracted from Rosa multiflora were 12.08, 11.82, 11.1 and 12.6 mg/g when using water, 70% ethanol, 70% methanol and 70% acetone as the solvent, respectively. The optimum conditions for extracting the phenolic compounds were 70% ethanol over for 12 hrs(11.82 mg/g). The electron donating ability and inhibition rate on ABTS of the 70% ethanol extracts were 97% and 92.2%, respectively while the antioxidant protection factor(PF) of the water extracts and 70% ethanol extracts were 1.79 and 1.34 PF, respectively. The TBAR (thiobarbituric acid reactive substance) value were $1.3{mu}M$ for the control and $0.15{mu}M$ for the 70% ethanol extracts. The inhibitory activity against ${alpha}$-amylase was 26% for the 70% ethanol extracts. The 70% ethanol extracts from Rosa multiflora Thunberg fruits exhibited antimicrobial activity against H. pylori, S. epidermidis, S. aureusand and E. coli with clear zone diameters of 14, 25, 14 and 13 mm, respectively when using $200{mu}g/mL$ of the phenolic compounds. An HPLC analysis identified 6 major phenolic metabolites in the Rosa multiflora Thunberg fruits extracts: rosmarinic acid, caffeic acid, chlorogenic acid, courmaric acid, protocatechuic acid and quercetin. In particular, the content of rosmarinic acid was the highest in the 70% ethanol extracts. Therefore these results indicate that 70% ethanol extracts from Rosa multiflora Thunberg fruits can be useful as a natural antioxidant and in functional foods.