Post-COVID -19 syndrome, also known as long COVID and post-COVID -19 condition, is a series of symptoms occurring after the acute phase of COVID -19 infection. The main symptoms are fatigue, headache, cognitive impairment, musculoskeletal pain, dyspnea, depression, and insomnia. Patients' quality of life and work ability can be seriously affected. Post-COVID -19 syndrome has gained the attention in the international medical community, leading to a series of studies on its pathogenesis, diagnosis and treatment options. Due to the effective epidemic prevention and control measures taken in China in the first three years of the global epidemic, the number of COVID -19 cases in China has been relatively low. With the adjustment of national epidemic prevention and control policies in early 2023, China has experienced large-scale infections nationwide in a short period. Currently, the treatment of acute COVID -19 in China has mostly concluded, and the diagnosis and treatment of post-COVID -19 syndrome will be the focus of hospitals at all levels in the future. This article summarizes the international research progress in post-COVID -19 syndrome, aiming to provide reference for the diagnosis and treatment of post-COVID -19 syndrome in China.