The invention discloses a pumped storage electricity generation system based on the weight pressurization technology in the technical field of electric energy storage. The pumped storage electricity generation system comprises a single-action single-piston-rod hydraulic cylinder, a low-pressure water pool, a weight acting on a piston rod and hydrogenation equipment. An energy storage electricity generation method of the hydrogenation equipment includes two stages of energy storage operation and electricity generation operation. The weight of the energy storage system acts on the piston rod through gravity, the weight descends to generate a high-pressure waterhead in the hydraulic cylinder, a pressure difference is formed relative to the low-pressure water pool, a pumped storage generator set is driven to generate electricity, and water enters the low-pressure water pool from a piston cavity through the pumped storage generator set. Therefore, the gravity potential of the weight is converted to potential of water, and then converted into electric energy through the pumped storage generator set. On the basis, a plurality of devices are operated in a parallel connection or cascade connection mode, continuous energy storage and electricity generation are realized, the cost is low, the efficiency is high, the service life is long, the ecology is not affected, and carbon emission of a power grid is lowered.