Abstract: [Purpose/Significance] In social media, the complex phenomenon of group polarization caused by the effect of network circle groups has brought serious challenges to the guidance and governance of online public opinion. This paper aims to explore the influencing mechanism of multi-dimensional environmental risk perception on group polarization in the network circle groups, and provide theoretical support and insights into the management of group polarization. [Method/Process] First, based on the protective motivation theory and the circle group structure theory, risk perception was divided into three dimensions: risk fact perception, risk loss perception and risk reaction behavior perception, and a network circle group was divided into three layers: point, line and structure. Based on this, a theoretical model of the relationship between risk perception and group polarization under the background of network circle groups was constructed. Second, taking the "6.10" hitting event as an example, a questionnaire was designed to collect sample data, and two sets of comparative data were obtained from the perspectives of randomly selected women and circled female groups, and the reliability and validity of the data were tested and analyzed. Finally, Amos26.0 software was used to establish a structural equation model (SEM) for empirical analysis of the research hypothesis in this paper, and the Bootstrap method was used to test the mediating effect of network circle groups, revealing the effect of risk perception on group polarization in network circle groups. [Results/Conclusions] 1) Compared with the random female group, the degree of homogeneity in the network group is higher, and the circle group effect is significant. 2) Risk perception has a significant positive impact on the formation of group polarization, in which the perceived risk response behavior has the most significant impact on group polarization. 3) Network circle groups have a significant positive influence on the formation of group polarization, among which "structure" has the most significant influence on group polarization. 4) Network circle groups play a mediating role between multi-dimensional risk perception and group polarization. The research not only reveals the generation path of network circle groups and risk perception on group polarization and the key factors affecting the occurrence of group polarization from the theoretical level, but also provides directions for relevant departments to manage group polarization and reduce public risk perception. This study has several limitations. For instance, SEM model setting and questionnaire design depend on the subjective experience and theoretical assumptions of researchers, and may have selectivity bias, so the model setting in this paper is subjective to a certain extent.

Key words: group polarization, risk perception, network circle group, structured equation model (SEM)