Abstract: Objective:To optimize the extraction technology of antioxidant substances from rhubarb by orthogonal test. Methods:The extraction technology was optimized by orthogonal design using DPPH antioxidant activity as the investigation target. Factors such as extraction time, ethanol concentration and solid-liquid ratio were evaluated and optimized by single factor and orthogonal test. Results:Results showed that:when ethanol concentration was 60%, solid-liquid ratio was 1:30 and extraction time was 30 min, the extract obtained the highest radical clearance rate (96.02%±1.36%). Conclusion:The extraction process could provide a simple and quick reference for industrial production. At the same time, it also provided the theoretical basis for the comprehensive utilization of rhubarb.