This paper discusses the relationship between the knowledge of biotechnology and public attitude towards genetically modified food. By examining the survey data of different times and different national conditions,it could be found that so far there hasn’t been a relatively stable positive correlation between the biotechnology knowledge in general and people’s attitude towards GM food or GM technologies. On the contrary,in different countries,as well as at different stages of the GM debates,the roles of biotechnology knowledge and the relevant audience education seem to be completely different in influencing people’s attitudes towards GM food. Through a systematic study of the media factors and psychological mechanism of the GM food controversy,this paper concludes that the major contributor to this difference is that in the controversial situation,people’s various instinctive psychological cognitive mechanisms have been greatly activated to replace their cognitive means of rational measurement via knowledge. This study provides an explanation framework to interpret the formation of polarization attitudes in scientific and technological disputes.