Given the seriousness of the problems that food security incidents have caused in recent years,consumers in favor of organic food show increasing concern to food security and their physical health.Based on the data obtained from 1 017 consumers in the first-tier cities like Beijing,Guangzhou,Shanghai and Shenzhen,this paper conduected a research by the application of the structural equation modeling approach and multiple-group analysis using the demographic as the regulated variable.The findings indicated that customers’ cognitive level on the concept,quality,externality and supplies of the organic food influenced their decision in purchase in a positive and obvious way.And the regulated variables,like gender,age,family income,educational background and fertility condition contributed a lot to the great discrepancy among diffrent groups.Consumers having children under 14 and high-income families served the main force to buy organic food.This paper further proposed policy suggestions to promot consumers to form purchase decision on organic food and stimulate the organic food consumption.