In order to select high-quality yam varieties in Mapu, Fujian, China, 7 yam clones (Dioscorea spp.) cultivated in Mapu were collected to determine their contents of polysaccharide, allantoin and basic nutrients, and their nutritional quality was evaluated by using fuzzy membership function method. The results showed that the average contents of polysaccharide, allantoin, protein, starch, crude fiber, ash, and total amino acids of the 7 yam clones were 2.98%, 4.79‰, 8.59%, 65.63%, 1.29%, 2.07%,and 6.28%, respectively. The Mapu yam clones were different in nutrient contents. MP1 had the highest content of allantoin, and MP6 had the highest contents of polysaccharide, protein, crude fiber and crude ash, while MP3 had the highest contents of total amino acid, essential amino acids, and flavor amino acid. Clones MP1, MP3 and MP6 contained higher general nutrients among the 7 clones according to the results of the fuzzy membership function analysis, and MP6 was the best in general nutrient quality. The results might provide some references for the selection and breeding of yam varieties in Mapu.