Abstract: The physical and chemical characteristics of gum rosin from Simao pine(Pinus kesiya var.langbinanensis) and Yunnan pine(Pinus yunnanensis) of Yunnan were studied.They were softening point(ring & ball),acid number,unsaponifiable matter,ethanol insoluble matter,ash,optical rotation and chemical compositions.There were 79 samples of gum rosin from Simao pine and 21 samples of gum rosin from Yunnan pine.They were from 11 producing areas of Simao pine and 4 producing areas of Yunnan pine.The results showed that averages of quality index of two gum rosins were superior to the technology required in GB/T 8145-87 and difference was not significant compared with those of Chinese.The chemical compositions of two kinds gum rosin in descending order were the same.They were abietic acid,palustric acid,neoabietic acid,dehydroabietic acid and communic acid.The significant level of optical rotations in enterprises was F=33.844 8＞F _(0.001,6,58)=4.395 8.Correlation between optical rotation and chemical compositions of gum rosin from Simao pine which palustric acid,abietic acid,dehydroabietic acid,isopimaric acid were that r_(0.001,12-2)=0.933 2~(***),r_(0.001,12-2)=-0.942 5~(***),r_(0.05,12-2)=-0.657 5~*,r_(0.05,12-2)=-0.693 9~*.