Abstract：Liver yang deficiency syndrome is easily neglected in the syndrome differentiation and treatment of chronic liver disease. This paper traces the theoretical origin of liver yang deficiency syndrome from physiology and pathology，and analyzes its significance and application in syndrome differentiation and treatment of chronic liver disease. It is suggested that there are many ways of origin of liver yang deficiency syndrome and liver qi deficiency syndrome and liver yang deficiency syndrome should be differentiated in clinical practice. The commonly used methods of supplementing the liver include treating the liver and supplementing the spleen， warming the kidney and the liver， nourishing the blood and dispersing the cold， nourishing yin and yang，and returning fire to its source，and there are corresponding prescriptions. Furthermore，combining the theory of liver yang deficiency syndrome with the clinical practice of yin jaundice disease， it is proposed that the core pathogenesis of the disease is "liver yang deficiency，damp-turbidity and fire from constraint"，and the treatment should be "opening acrid herbs and promoting descent bitter herbs as well as warming liver yang" as the major method.