1. Objectives: This study was carried out to investigate the Sasang constitutional equilibrium functional difference according to drinking and smoking. 2. Methods: We analyzed the data of 300 adults(194 males, 106 females), who visited Cheonan oriental hospital of D univ. for medical examination, which includes Sasang constitution examination, equilibrium function test, questionnaire. We evaluationed the equilibrium function by measurement of open eyes and close eyes trace length, using the posturography system, according to drinking groups, smoking groups and drinking-smoking groups. 3. Results and Conclusions: The results were as follows : 1) In all subjects, trace length of heavy-drinker was significantly higher than non-drinker, trace length of smoker was significantly higher than non-smoker, trace length of drinker and smoker was significantly higher than non-drinker and non-smoker, trace length of male was significantly higher than female. 2) In Soyangin, trace length of middle-drinker was significantly higher than non-drinker. 3) In Taeumin, trace length of heavy-drinker was significantly higher than non-drinker, trace length of smoker was significantly higher than non-smoker, trace length of drinker and smoker was significantly higher than non-drinker and non-smoker. 4) In Soumin, trace length of drinker and smoker was significantly higher than non-drinker and non-smoker. The above results show that driking and smoking are one of main causes to decrease equilibrium function, specially the case of at once drinking and smoking are a potent influence. Also in Taeumin, comparing to different consitutions, the above results show that it is more obvious that drinking and smoking are influence on decrease of equilibrium function.