Lin Lin and Wang Jingying took social workers as the research object who worked during the period of epidemic prevention and control under the background of COVID-19, the major public health event of in China. It referred to the international research on public opinion and selected 63 related hotly discussed articles containing keywords “epidemic+social workers “and “epidemic+volunteers” in the WeChat public platform, and public comments on the WeChat public platform, the new Chinese Internet media. Lin Lin and Wang Jingying considered the struggle of social workers during the pandemic and must appreciate him for taking them as research objects. The WeChat platform used by the author namely "5 W” communication model helps to study public opinion evolution is very much compatible. American political scientist Harold. D. Laswell proposed the “5 W model” of cultural communication in The Structure and Function of Communication in Society that is, human communication activities are composed of five elements: Who-Says what-In which channel-To whom-With what effect. The research used this model to an Alize the communication process of public opinion, and conducted research from five parts: public opinion evolution, text content, communication media, audiences, and public opinion influence.