The invention discloses a large-scale mechanical water fetcher which comprises a water reservoir and a water storage space arranged on the upper surface of the water reservoir, wherein a water feeding pipeline is arranged at the center of the water storage space on the water reservoir; the upper and lower parts of the water feeding pipeline are respectively located in the water storage space and at the bottom of the water reservoir; a hollow structure is formed in the water feeding pipeline; limiting rings are respectively fixed with upper and lower ends in the water feeding pipeline; through hole structures are formed at the centers of the limiting rings; a piston is arranged between the two limiting rings in the water feeding pipeline; the through hole structure is formed at the center of the piston. The large-scale mechanical water fetcher utilizes a principle of oil well to pump the underground pure water source on the basis of the pressure principle, so that people can use the pure water source and the water drinking of people can be guaranteed. Besides, the large-scale mechanical water fetcher also utilizes a lever principle, so that the output power at each time of a motor can be reduced and the service life thereof can be prolonged.