Objective> To explore whether the preparation of Rosa Davurica Pall (RDP) has biological protective effect on the oxidative stress. Three different doses were used to test animals for protecting liver, anti-radiation,anti-oxidation and surrival time of drosophila. The value of GOT and GPT and the pathology tissue integral of the high dose group decreased obviously in the study group as compared with that of the control.The survival time and rate of the study group increased obviously compared with that of the control,while the SOD activity increased obviously. The subduple death time and average lifespan in the 1.08% dosage of the male drosophila extend obviously as compared with that of the control,so does the average lifetime of female drosophila. The preparation of Rosa Davurica Pall(RDP) has protective effect toward the injuried liver cell from reactive oxygen spicices respectively with CCl 4 and radiation,protects the animals from death,reduces the oxidative stress level of the senescent rat,so as to consider that RDP extent the lifespan of the drosophila is possibly concerned with reducing the oxidative stress level.The preparation of RDP has biological protective effect of reducing the oxidative stress level.