This study investigated effect of difference in dietary behavior and lifestyle by nutrition knowledge level among college students [n=306] in Pyeongtaek area. Based on nutrition knowledge as described in our previous study, students were divided into three groups: low (score<20.5), medium (score=20.5-28.0), and high (score28.0). The high group (score of 2.16) showed higher eating frequency of seaweed than low (score of 1.44) and medium groups (score of 1.60),(p<0.05). However, the high group showed lower value (score of 1.74) of fast foods than other groups (low: score of 2.59; medium, score of 2.17),(p<0.05). Drinking amount (≥1 bottle),(p<0.05) and smoking (p<0.05) were also lower in the high group than in other groups. Nutrition knowledge level was negatively correlated with snack intake (-0.129),(p<0.05), drinking frequency (-0.146),(p<0.05), and smoking amount (-0.132),(p<0.05). Nutrition knowledge was negatively affected by factors of high intake of snack (p<0.05), night eating (p<0.05), high drinking frequency (p<0.05), and smoking (p<0.05). Overall analysis revealed that nutrition knowledge level was positively associated with good dietary behaviors and lifestyle, including low drinking and smoking. Therefore, a national nutrition education policy is need to improve nutrition knowledge of college students. It may lead to good eating behaviors.