Colorless transparent liquid with special odor of aromatic hydrocarbon. It is a mixture of 45%～70% m-xylene, 15%～25% p-xylene and 10%～15% o-xylene. It is soluble in absolute ethyl alcohol, diethyl ether and many organic solvents, almost insoluble in water. Relative density is 0.86. Boiling point is 137～140℃. Refractive index  (n?20D) is 1.4970. Flash point is 29℃. Inflammable. Its vapor can generate explosive mixture with the air, explosion limit is about 1%～7%(volume). Low toxicity, medium lethal concentration(rat, inhalation) 0.6 7%/4h.