As one of the five global major extinction events in the geological history, the Late Triassic mass extinction event resulted in the extinction of approximately 53% of genera and 80% of species in marine ecosystems. A systematic review of extinction patterns and mechanisms at the Triassic—Jurassic boundary (TJB) is of great practical significance for predicting the recurrence of mass extinction events. Methods: The evolution of terrestrial flora, terrestrial tetrapods and marine organisms at the end of the Triassic was analyzed based on paleontological data from multiple profiles around the world. The causes of the mass extinction at the end of Triassic were discussed in terms of ocean acidification, ocean anoxia, greenhouse effect, ancient wildfire event and celestial impact.Results:The eruption of the Central Atlantic Magmatic Province (CAMP) released a large amount of CO2, SO2 and CH4. The rising of sea level and the decreasing of species habitat area caused by greenhouse effect, ocean acidification and ocean hypoxia directly threatened the living environment of marine and terrestrial organisms. Furthermore, the global forest fires caused by greenhouse effect resulted in the reduction of land plants. A large amount of plant charcoal debris moving into the ocean resulted in eutrophication, accompanied by ocean acidification (carbonation and sulfur acidification) and ancient ocean productivity collapsing. Biological mass extinction in different geological periods used to be accompanied by severe environmental changes. These changes during the Late Triassic mass extinction included ancient atmosphere components and temperature instability, frequent wildfire and ocean acidification, rising sea level and water anoxic event, and the combination between them eventually led to the instability of the Late Triassic global ecosystems. Three significant negative carbon isotope excursions can be identified in several outcrops at the Triassic—Jurassic boundary (TJB), the largest taking place at the end of the Rhaetian, earlier than the TJB. Conclusions:The CAMP eruption was the direct cause of the mass extinction of TJB, and the combined effect of ocean acidification, ocean hypoxia, greenhouse effect and frequent occurrence of ancient wildfires caused by volcanic eruption was the direct cause of the mass extinction of organisms at the end of Triassic. Although the TJB biological mass extinction was a global event, it was not a one- off event, and had the characteristics of phased, non- synchronous, regional and selective.