The invention discloses a construction method of an underground large water-flow mine emergency water sump. When in the multi-middle-segment exploitation of a mine, the middle segment at the bottommost part is locally exploited in advance through an open-stope method and a mined-out area is formed as the emergency water sump of the mine; when fragmentary and leftover orebodies under or beyond exploitation exist in a mineral deposit, a set of small production system is formed at a position below the lowest exploitation level by utilizing blind incline shaft or blind vertical shaft exploitation, and the orebodies at a boundary part or the fragmentary orebodies are mined out to leave the mined-out area as the emergency water sump. The capacity of the emergency water sump is designed according to the water permeation capacity of 8-10 hours, the highest elevation of the emergency water sump is below the lowest production level, an inlet thereof is communicated with a haulage roadway at thelowest mining level, a patio is arranged at the upper part of the emergency water pump, and the patio is communicated with a level and an air shaft at the upper middle segment. The emergency water sump not only can have remarkable effect for the emergency capability for water permeation accidents of a limited water source, but also strives for valuable self-rescue time for hours when disasters inthe type of unlimited water sources, such as underground rivers, surface water sources, and the like of the mine occur.