Background: In contrast to abundant research on the various acute mental effects of COVID-19, the long-term influences of the pandemic are still underexplored in China owing to the paucity of assessment tools. The Pandemic Disengagement Syndrome Scale (PDSS) assesses people's social disengagement as a lasting psychological consequence in Western countries during the post-COVID-19 pandemic era. However, its generalizability across cultures is untested. Objectives: The present studies aimed to validate Chinese PDSS and compare disengagement syndrome levels among China, the United States and Italy. Method: In Study 1, a Chinese version of the PDSS was developed, psychometric properties including factor structure, internal consistency, measurement invariance across gender and country, discriminant validity, and test-retest reliability were tested. Study 2 examined demographic differences in the pandemic disengagement syndrome in China and compared Chinese PDSS scores and those in the United States and Italy (Ns = 415, 455, 826). Results and Conclusion: The findings indicated that disengagement syndrome may exist among Chinese people even substantially after the acute phases of the pandemic. Meanwhile, the Chinese PDSS demonstrating acceptable psychometric features can be a valid instrument to assess the syndrome. Several possible reasons for the persistence of disengagement in China are discussed.