Objective : To establish a standard for discriminating between deficiency syndrome and excess syndrome and selecting reinforcing or reducing method. Methods :Deficiency syndrome and excess syndrome were divided into excess of pathogenic factor with sufficiency of vital energy syndrome, weakness of pathogenic factor with deficiency of vital energy syndrome and excess of pathogenic factor with deficiency of vital energy syndrome. Documentary survey was done for each case. Results : Excess of pathogenic factor with sufficiency of vital energy syndrome is an excess syndrome and a reducing method must be used. Weakness of pathogenic factor with deficiency of vital energy syndrome is a deficiency syndrome and a reinforcing method must be used. Excess of pathogenic factor with deficiency of vital energy syndrome is related to deficiency syndrome and a reinforcing method must mainly be used. Conclusions :Deficiency or sufficiency of vital energy is the standard for discriminating between deficiency syndrome and excess syndrome and selecting a reinforcing or reducing method.