Abstract: To investigate the optimum technology for extraction of antioxidants and the extracts' anti-inflammatory activity from pitaya flower, the antioxidant activity in vitro of the extracts from pitaya flower was determined by scavenging capacity of DPPH·and·OH.The effects of extraction temperature, solid-liquid ratio, extraction time and ethanol concentration were studied through the single factor experiments, and L₉ (3⁴) orthogonal test was used to explore the antioxidant activities of extracts from pitaya flower in vitro. The results showed that, the optimized conditions were:70% ethanol, the solid-liquid ratio of 1:30 g/mL, when treatment time was 3.0 h at 75℃. Under these optimized conditions, the IC₅₀ for scavenging capacity of the extracts against DPPH·and·OH were 0.273, 0.288 mg/mL, respectively. And within a certain range, the higher the concentration of the crude extract, the better its antioxidant activity, which had an obviously dose-effect relationship. Moreover the extracts under the optimized conditions could decrease secretions of NO in LPS-induced RAW264.7 macrophage cells, and the anti-inflammatory activity for the extracts increased in a concentration-dependent manner with IC₅₀ value of 13.94 μg/mL. The extracts had good antioxidant activity and anti-inflammatory activity in vitro.