Among adolescents and young adults, self-reported baseline psychological distress was quite high during the COVID-19 pandemic. As a vulnerable group, college students suffer from serious psychological problems such as anxiety and depression during the COVID-19 pandemic. Despite the fact that COVID-19 no longer constitutes a public health emergency of international concern and the reduction of COVID-19 pandemic restrictions in March 2023, the change of college students' mental health remains unclear. In March and June 2023, college students in Kunming, China, were investigated by the Self-Rating Anxiety Scale, Self-Rating Depression Scale, and Pittsburgh Sleep Quality Index. After the COVID-19 pandemic restrictions were reduced, the results of the scale indicated anxiety (-0.6%, 21.6%-21%), mild anxiety (+ 0.5%, 16.50%-17.0%), moderate anxiety (-0.7%, 3.94%-3.2%), and severe anxiety (-0.4%, 1.2%-0.8%). Depression (-8.1%, 37.2%-29.1%), mild depression (-5.2%, 19.4%-14.2%), moderate depression (-2.2%, 16.7%-14.5%), or severe depression (-0.7%, 1.1%-0.3%) among college students. Good sleep quality (0%, 72.3%-72.3%) and poor sleep quality (0%, 27.7%-27.7%); anxiety or depression (-6.5%, 39.7%-33.2%) among college students. The incidence of anxiety and depression in college students was reduced, after the reduction of COVID-19 pandemic restrictions.