Using glucose as standard and DNS as color developing reagent, the content of total reducing saccharide in Hainan Dioscorea esculenta (Lour.) brukill was determined by spectrophotometry. The results showed that the maximum absorption wavelength of the sample was 480nm. The maximum recovery rate was determined as 101.9%, and the minimum was 99.7%. The relative error was ±1.9%. The content of total reducing saccharide and starch in Hainan Dioscorea esculenta (Lour.) brukill was 71.08% and 63.97%, respectively.