Abstract: During the outbreak of COVID-19, World Health Organization (WHO) put forward a new concept: Infodemic. Social media users receive and share a great amount of information every day. Excessive information of mixed quality, which is the typical feature of Infodemic, goes beyond users’ information processing ability and become a cognitive burden for them. It harms people’s physical and mental health. This paper employs the SSO model in social psychology as the theoretical framework, studies the influence of Infodemic on college-students’ social media negative information behavior by using fatigue and psychological reactance as mediator variables. It collects data through questionnaires and uses SPSS 25.0 and AMOS24.0 for confirmatory factor analysis and hypothesis testing. It reveals that overloaded information delivered by social media and overloaded information sharing have significant positive effects on fatigue and psychological reactance; low-quality information including rumors and disinformation has significant positive effects on psychological reactance; users’ fatigue and psychological reactance have significant positive effects on ignoring and shielding behavior on social media. It further discusses how to alleviate the negative influence of Infodemic on college students from the perspectives of social media management and the improvement of information literacy. This research has important practical implications for the guidance of the normative mobile information behavior of college students.

Key words: COVID-19 , Infodemic , Information overload , Information behavior, SSO Model