Abstract: Objective:This study was designed to compare biological activities of Dendrobium. huoshanense and Dendrobium officinale(Yueqing,Yunnan)in vitro. The immunity activities,antioxidant activities,cell oxidative stress injury,antitumor activities and α-glucosidase inhibitoryassay were analyzed. Method:Three kinds of Dendrobium water extracts with different concentration were used to activity experiments in vitro,including the release of NO by stimulating macrophage RAW264.7,the ability of clearing ABTS free radicals,the total antioxidant capacity with FRAP method,the ability of preventing the cell PC12 aging induced by H₂O₂,the activity of hepatoma cell HepG2 and the activity of intracellular α-glucosidase of insulin resistance HepG2 model. Results:The results showed that the extract of Dendrobium huoshanense could significantly stimulate macrophages to release NO in vitro and strongest antioxidant of ABTS scavenging ability and Ferric ion reducing power. The Alamar Blue results indicated Dendrobium huoshanense extracts at the concentration of 200 μg/mL had better protective effect on activity decrease of PC12 cell induced by H₂O₂,and the recovery ratio was 40.52%. In addition,the water extracts from 3 species of Dendrobium could inhibit in growth of HepG2 cells. The Dendrobium huoshanense extracts(200,400 μg·mL^-1)had stronger inhibitory effect on α-glucosidase than other fragments in insulin resistant model HepG2 cells,while water extracts from 3 species of Dendrobium had no activity at 100 μg·mL^-1. Therefore,Dendrobium huoshanense had considerable anti-hyperglycemic activities. Conclusion:Dendrobium huoshanense had a better effect than Dendrobium officinale in enhancing biological activity such as immunity,anti-tumor,anti-oxidation,anti-aging and blood sugar lowering.