BACKGROUND: During endotracheal intubation, extubation, tracheotomy, and tracheotomy tube replacement, the splashed airway secretions of patients will increase the risk of transmission of SARS-CoV-2 and many other potential viral and bacterial diseases, such as influenza virus, adenovirus, respiratory syncytial virus, rhinovirus, Middle East respiratory coronavirus syndrome (MERS-CoV), Streptococcus pneumoniae, and Mycobacterium tuberculosis. Therefore, it is necessary to establish a barrier between patients and medical workers to reduce the risk of operators\' infection with potentially pathogenic microorganisms. METHODS: We designed a "safety cap" that can be connected to the opening of an endotracheal tube or tracheotomy tube to reduce the diffusion area of respiratory secretions during the process of endotracheal intubation, extubation and tracheotomy tube replace, so as to reduce the infection risk of medical workers. RESULTS: Through a series of hydrodynamic simulation analysis and experiments, we demonstrated that the use of "safety cap" can substantially limit the spatter of airway secretions, so as to improve the hospital sanitation. CONCLUSION: The "safety cap" can effectively limit the dissemination of patients\' respiratory secretions, thus reducing the risk of potential diseases transmission and may have certain application prospects.