Abstract: The major challenge of emerging infectious diseases in the future is to timely identify new pathogens. The emerging infectious diseases in future are caused by new microorganisms. However, over 99% bacteria or virus on earth have not been discovered yet. Therefore, we propose a reverse microbial etiology. The main contents include:discovering, isolating and naming new microorganisms; evaluating the potential pathogenicity or public health significance of newly discovered microorganisms; proposing the catalogue or list of the new microorganisms that may cause outbreaks in the future; studying the mechanism, methods, techniques and strategy for detection, diagnosis, treatment, prevention and control; and preventing SARS-like outbreak in future.