The anti-aging activities on Caenorhabditis elegans of a polysaccharide,O-acetyl glucomannan (BHP-1),purified from bulbs of Lilium davidii var. unicolor Cotton,were assessed by observing the mean lifespan,reproduction,pharyngeal pumping and stress response on nematodes.Additionally,the fluorescence intensity of lipofuscin and the level of reactive oxygen species (ROS) were detected.Also the activities of superoxide dismutase (SOD),catalase (CAT) and contents of malondialdehyde (MDA) were determined by the kit method.The results showed that BHP-1 effectively delayed the aging of C. elegans in a dose-dependent manner.When the concentration reached 4 mg/mL,BHP-1 extended the mean lifespan of C. elegans by up to 40%,61% (P<0.01) and 50% (P<0.05) under normal,thermal and oxidative stress culture conditions,respectively.Moreover,BHP-1 remarkably decreased the ROS and lipofuscin level of C. elegans while increased the reproduction and feeding ability duration of the nematodes.Further study illustrated that BHP-1 could significantly enhance the activity of antioxidant enzymes in nematodes,compared to the control,BHP-1 with the dose of 4 mg/mL strongly increased the activity of SOD and CAT by 39.03% (P<0.01) and 41.89% (P<0.05),and decreased the level of MDA in  C. elegansby 52.59% (P<0.005).It was inferred that BHP-1 prolonged the lifespan of wild type N2 C. elegans mainly by elevating the function of nematode antioxidant defense systems without damaging the reproductive and feeding abilities of nematodes.