Major emergencies cause massive financial risk and economic loss. In the context of major emergencies, we propose the GPD-CAViaR model to depict the extreme risks of financial sectors, and utilize the TVP-SV-VAR model to analyze their transmission effect. We find that (ⅰ) the securities sector has the highest extreme risks among the four financial sectors; (ⅱ) when major emergencies occur, the extreme risks of various financial sectors increase rapidly; (ⅲ) the transmission effect in short term is stronger than that in medium and long term; and (ⅳ) the transmission effects at different time points are relatively consistent.