The present invention discloses a timing capacitor. The timing capacitor comprises a shell, a capacitor component group and a timer. The inside of the shell forms a cavity, the top of the shell formsan opening, the shell is provided with a sealing plate used for closing and opening the opening, and the bottom of the shell is provided with a metal panel. The capacitor component group comprises a hard insulating inner liner, an electrolyte, a dielectric baffle, an electrode bar, connecting terminal(s), an insulating filling material and a discharge resistor. The top of the hard insulating innerliner has no cover seal, the top of the hard insulating inner liner is provided with a coating layer, and the insulating filling material and an adsorbent cover the coating layer. The hard insulatinginner liner is located in the shell, the hard insulating inner liner is tightly connected with the inner wall of the shell, the top of the hard insulating inner liner is provided with the insulatingfilling material, and the electrolyte is located in the hard insulating inner liner. The timer is arranged in the upside of the inner cavity of the shell, the timer is fixed on the lower surface of the sealing plate, and the timer is connected with the connecting terminal(s) via wires. The present invention provides a timing capacitor capable of blocking a capacitor circuit.