The invention discloses a line hydraulic energy storage system, which comprises an oil source (1), an electromagnetic reversing valve (2), a first hydraulic pipeline (3), a second hydraulic pipeline (4), a pressure sensor (5), at least one hydraulic cylinder (6) and at least one energy storage unit (7), wherein the oil source (1) provides power, the pressure sensor (5) is used for detecting the liquid pressure of the second hydraulic pipeline (4), the at least one hydraulic cylinder (6) and the at least one energy storage unit (7) are distributed along the line of the first hydraulic pipeline (3) and the second hydraulic pipeline (4), and meanwhile, the invention also discloses a line hydraulic energy storage method. The method and the system provided by the invention are particularly applied to a high-work-flow-rate hydraulic system adopting multiple executing elements in intermittent simultaneous work, a small-delivery-capacity hydraulic pump can be used for meeting fast acting requirements of the system, the system structure is compact, the arrangement is flexible, the installing space is saved, and the production cost is reduced.