The COVID-19 global health crisis has caused widespread concern among people worldwide, affecting their mental health and behavior. People’s response to this crisis varied greatly from country to country, with cultural tightness being one of the key influences. Countries, like China, with tighter cultures demonstrated a clear advantage. Its strict anti-pandemic measures prompted the population to adopt more effective protective behavior to curb the spread of the virus while protecting their mental health. However, research on people's attitudes towards such cultural tightness is lacking. Additionally, previous studies have mainly focused on individuals' concern of their own infections, neglecting their concern about the infections of people around them. Lastly, it is unclear whether this process varies during and post COVID-19 lockdown. To address those questions, a study of 614 mainland Chinese participants was conducted. The results indicate that, Chinese individuals were more concerned about their family, significant others and the public being infected than they were about themselves being infected. In terms of infection concern of oneself and public, individuals who more concerned desired more cultural tightness, which in turn led to better mental health and greater engagement in protective behavior. Interestingly however, people who more concerned about their family members being infected expect a looser culture during the lockdown and desire a tighter culture post-lockdown, which promotes more protective behavior and better mental health. Furthermore, the association between the desire for tightness in response to concern about COVID-19 infection and promoting mental health and protective behavior was more pronounced post-lockdown compared to lockdown phase.