Abstract: To extend the durability of timber, some research have been done on the timber factors' analysis and expression. Jujube timber, Northeast China ash timber, poplar timber are chosen as the samples, to measure the carbon-nitrogen content of the timbers and the lignin, analyze the ratio of carbon-nitrogen content as well; and to measure the lignin content, lignin density, water soluble lignin density, the extract content of soluble in benzene, alcohol solution and total extract density, compare the FTIR of timber and lignin, research the ratio of guaiacyl and syringyl. Results indicated that the air dry density of Jujube, the best durability timber, is 0.93 g/cm3, and as the FTIR of Jujube timber is 1 633 cm-1, during the stretching vibration of the carbonyl(C=O), there is wave crest existence. The value of G/S is 0.975, the nitrogen content of Jujube timber is 0.274% and nitrogen content of Jujube lignin is 0.444%, these values are the minimum compared with those of the other two timber samples. The carbon-nitrogen content ratio of Jujube timber and of Jujube lignin is respectively 180 and 135, the density of Jujube lignin is 184.39.7 mg/cm3, the total extract density is 88.13.5 mg/cm3, compared with Northeast China ash timber, poplar timber, these numerical values are the maximum.