Objective To investigate the current status of intensive care unit (ICU) competency and infectious disease emergency response capability of nurses involved in the critical care of corona virus disease 2019 (COVID-19) in Shanghai and to analyze the influencing factors. Methods A convenience sampling method was used to select 234 nurses from six tertiary care hospitals ICU coping with COVID-19 coping ICU in Shanghai as study subjects. According to the ICU working experience prior to the pandemic, the nurses were divided into ICU and non-ICU groups. All the subjects were surveyed with the ICU nurse competency questionnaire and the health care workers’ infectious disease emergency response competency questionnaire. Results Of the 234 valid questionnaires returned, 44 belonged to the ICU group and 190 were from the non-ICU group. Although both groups performed well on ICU competency, the score of ICU group (82.23±10.02) was significantly higher than that of the non-ICU group (71.14 ±11.36) (P<0.05), with 70.5% of the ICU group maintaining at the good level and above, while only 56.9% of the non-ICU group reaching that level. The infectious disease emergency response competency score was (3.62±0.70) in the ICU group and (3.50±0.65) in the non-ICU group.The ICU group had slightly higher prevention, preparedness, rescue and overall response capabilities than the non-ICU group. Multiple linear regression showed that the infectious disease emergency response competency level and the presence of emergency response experience were the main factors contributing to the competency of nurses involved in the critical care of COVID-19 (P<0.05). Conclusions The total nursing competency score and overall professionally were higher in the ICU group than in the non-ICU group, but there were still some nurses with lower competency in the ICU group requiring further training. The infectious disease emergency response ability was at an intermediate level in both groups. The competency of ICU nurses could be attributed to multiple factors, such as extended work experience, particularly on infectious disease emergency.