Objective To investigate a suspected outbreak event of Mycobacterium abscessus (Mab) infection in department of pulmonary and critical care medicine in a hospital, provide basis for the precise prevention and control of healthcare-associated infection (HAI). Methods On-site epidemiological investigation and environmental hygienic detection were carried out in patients with Mab infection following fiberbronchoscopic bronchoalveolar lavage in the department of pulmonary and critical care medicine in this hospital, and targeted intervention measures were proposed. Results From September 7 to October 20, 2022, a total of 344 cases of bronchoalveolar lavage were performed for patients in fiberbronchoscopy room of department of pulmonary and critical care medicine. Mab was detected from bronchoalveolar lavage fluid (BALF) of 10 patients. Through on-site and follow-up investigation, the initial case was defined as community-associated infection, and the other 9 cases were due to the contamination of specimens. A total of 33 environmental hygienic specimens were collected, and no Mab was detected. The event was effectively controlled after standardizing the process of bronchoscope decontamination, strengthening the infection management of ward and bronchoscopy room, and strictly implementing the certificate system of bronchoscopy decontamination personnel. Conclusion This pseudo-outbreak is due to the contamination of fiberbronchoscope by Mab. Timely identifying risk factors as well as taking targeted prevention and control measures can effectively control the spread and prevalence of Mab infection.