The invention relates to the field of Stirling engines, in particular to a double-acting passive energy storage type piston. The double-acting passive energy storage type piston structurally comprises a flexible piston, wherein the flexible piston is hermetically connected with a sealing flange, the sealing flange is connected with a cold cylinder, the cold cylinder is hermetically connected with a hot cylinder, the sealing flange and the cold cylinder are connected with an elastic sealing head through V-shaped piston supports and a connecting piece, the elastic sealing head is fixedly connected with a piston cylinder through an anti-skid device, a pressure balance hole is formed in the piston cylinder, a spring fixing device is arranged in the hot cylinder, and a spring is arranged between the bottom of the piston cylinder and the spring fixing device. The double-acting passive energy storage type piston has the beneficial effects that when an engine is shut down, the spring plays a role in supporting, the piston cylinder is prevented from being deformed by dragging and hanging caused by the gravity of the piston cylinder, so that the service life is prolonged; and when the engine runs, when the piston cylinder moves downwards, the spring is compressed to store potential energy, when the piston cylinder moves upwards, the elastic potential energy is released, so that larger power is provided for the piston cylinder to move upwards, and the efficiency of the engine is improved.