Oil content of whole fruit were determined using fruit of Idesia polycarpa Maxim.from thirteen populations,and oil contents of pulp and seeds were determined using the fruit from five population.The results were as follows:(1)There were significant differences in oil contents of whole fruit among thirteen populations,and the oil contents of fruit from populations in Sichuan Province were obvious greater than those from other populations,in addition.There were also significant differences in oil contents of fruit in each population,and degree of extreme variation were large.(2)Oil contents of pulp from the five populations were greater than those of seeds,while coefficient of variation and relative range of pulp were less than seeds.(3)Clustering analysis indicated that oil contents of fruit from seven populations included chaotian et al.were greater than that of others,and coefficient of variation of them were less than that of others.These populations were clustered to a class and could be as materials for further breeding.Geographical factors such as elevation and so on had different levels of effects on oil contents of fruit.(4)Refractive index of fruit oil from five populations were higher,while acid value were lower,which indicated that oil of I.polycarpa had excellent quality and high purity.There were significant differences in Iodine value of I.polycarpa oil from different populations,which reflected the obvious difference of degree of unsaturation of oil.