The formation of public opinion is the result of the interaction of mass communication, interpersonal communication and people's cognitive psychology of "public opinion environment"; The opinions emphasized by mass media are easily regarded as "majority" or "superior" opinions because of their openness and universality; The pressure and sense of security brought by this kind of environmental cognition will lead to the spiral expansion process of "the voice of inferior opinions" in interpersonal communication and lead to the overwhelming "majority opinion" public opinion in social life.