Objective To understand the infection status and disease spectrum distribution of patients with multidrug-resistant organism (MDRO) infection in an intensive care unit (ICU), and provide basis for the prevention and control of MDRO infection. Methods Clinical data of patients in the ICU of a tertiary first-class hospital from January 2018 to December 2020 were analyzed, differences in disease spectrum of patients with MDRO infection in ICU (case group), patients without MDRO infection in ICU (control group), and patients with MDRO infection in non-ICU were compared. Results The overall constituent of patients with MDRO infection in ICU showed an upward trend; the majority of infected patients were male, most of whom were the elderly, mortality of MDRO-infected patients was higher than that of uninfected patients. MDRO-infected patients directly admitted to ICU accounted for the highest proportion in the whole MDRO-infected patients. Acinetobacter baumannii ranked first among strains isolated from MDRO-infected patients in ICU, Escherichia coli ranked first among strains isolated from MDRO-infected patients in non-ICU; the disease spectrum of the first two groups was similar, with respiratory diseases ranking first, mainly pulmonary infection; the disease spectrum of patients without MDRO infection in ICU was hypertension, which was different from that of infected patients. The order of different diseases also changed in varying degrees with the increase of years. Conclusion The disease spectrum of patients with MDRO infection is complex and diverse, scientific, accurate and standardized treatment should be achieved, treatment of respiratory diseases should be paid attention, and the implementation of infection prevention measures should be strengthened.