Background Critically ill patients with coronavirus disease 2019 (COVID-19) were surging and far outnumbered existing beds. Aims To describe how to rapidly convert general wards to intensive care units for critically ill patients with COVID-19. Materials and Methods Comprehensive assessment and analysis of available resources and standard requirements. Results The ICUs were successfully assembled in 4 days. The conversion included environment reconstruction, configuration and management of equipment, information system construction and human resource allocation. A total of 172 critically ill patients had been admitted to the contemporary ICUs and none medical staff was infected. Discussion The epidemic situation of COVID-19 poses a great challenge to various management departments of the hospital, especially for critically ill patients with a high mortality rate. To save more critically ill patients, the conversion of a general ward to a quarantine ICU ward must be completed in a short time, and the optimal allocation of resources must be appropriate to ensure that the medical team works effectively and is of high quality. In face of the overloaded medical system, the ideal non-negative pressure ward is hard to achieve. However, we have demonstrated with evidence that our conversions are effective in both providing care to critical patients and protecting the safety of our staff. Conclusion The conversion is successful and the running experience would be a reference for hospitals in other areas nationally or globally.