The invention discloses a hydraulic accumulator for a propellant tank in a spacecraft. The hydraulic accumulator comprises an air guide tube, a cover plate, an outer shell, blades, a support column, a base, channel window pressing plates, a channel window meshes, hydraulic accumulator meshes, a fixing block and hydraulic accumulator mesh pressing plates, wherein the blades are uniformly distributed on and fixed to the support column in the radial direction to form a whole structure, and the whole structure is mounted on and fixed to a circular partition plate in the base; the hydraulic accumulator meshes are pressed on the circular partition plate in the base through the hydraulic accumulator mesh pressing plates and then fixed; the channel window meshes are pressed on the outer side of a cylinder wall of the base through the channel window pressing plates and then fixed; the outer shell is fixed at the top end of the base, the cover plate is fixed on the outer shell, and the air guide tube is fixed on the cover plate through the fixing block. The hydraulic accumulator disclosed by the invention is simple in structure, high in strength and reliability, large in liquid storage quantity and wide in work application range, has the function of repeatedly and circularly filling liquids to the hydraulic accumulator and discharging the liquids from the hydraulic accumulator, is large in liquid filling and discharging rate, and meanwhile has the capacity of realizing ground repeated filling.