The constituents of oil from Broussonetia papyrifera (L.)Vent. fruits were analyzed qualitatively and quantitatively by means of GC-MS-COMPUTER DATABASE system. 27 compounds from the oil were identified. Among them, linoleic acid, methyl palmitate, oleic acid and linoleic acid ester were major constituents, which relative contents were 63.982%, 20.914%, 4.263% and 3.505% respectively. And the absolute content of linoleic acid was determined (51.26%) by GC external standard method. Analyzed key physical constants related to its quality standard, the results indicated that relative density, refraction and pH were 0.911 7-0.914 0,1.473 1-1.473 5 and 5.50-5.78 respectively.