Atmospheric precipitation storage underground reservoir system and construction method

An atmospheric precipitation storage underground reservoir system is disclosed and used for mountainous areas or islands covered by complete bedrocks, a reservoir boundary is formed by drilling boundary shafts between planned boundaries of the complete bedrocks and performing directional fracturing between the boundary shafts, and rocks in the reservoir boundary form bedrock fractures through drilling and fracturing. A fracture reservoir is formed in the reservoir boundary, after atmospheric precipitation falls to the fractures in the surfaces of the rocks and permeates into the reservoir to be stored to form underground water, the underground water cannot be lost and wasted from the surfaces of the rocks, and the stored underground water is taken out through a water taking well; in addition, by building an earth surface water gathering and collecting channel, rainfall is guided to a fracturing well to enter the fractured reservoir, and the water storage efficiency is improved; and according to the undergroun