Objective: To explore Aspergillus infection's risks, treatment, and prognostic factors in critically ill COVID-19 patients. Methodology: Retrospective analysis of 50 critically ill COVID-19 patients' data. Patients were divided into Aspergillus infection group (10 cases) and non-Aspergillus infection group (40 cases) to examine risk factors and compare hospitalization length, expenses, and survival outcomes. Results: Logistic regression showed a significant correlation between Aspergillus infection and diabetes history, and steroid use duration in COVID-19 patients. Diabetes increased Aspergillus infection risk 9.708 times (not statistically significant). Each extra steroid use day raised infection risk by 25.6%. The Aspergillus infection group had longer hospital stays, and higher costs (p < 0.05) but surprisingly higher survival rate than the non-infection group (p < 0.05). Conclusions: The main risk factor for Aspergillus infection in critically ill COVID-19 patients is steroid use duration. The infection group had longer hospital stays and higher costs, and Aspergillus infection affected the survival duration of critically ill COVID-19 patients.