The invention relates to a door head body of a ship lock valve, in particular to a door head body for relieving the cavitation of a built ship lock valve; the door head body comprises a door head, a pressure plate, a P-shaped water stop, a cushion plate, a base plate and a panel; the P-shaped water stop is arranged between the pressure plate and the cushion plate, the base plate is arranged below the cushion plate, the panel is arranged below the base plate, an air pipe is additionally arranged in a valve well, a negative pressure plate is arranged at the position of the head door, the air pipe is welded wit the negative pressure plate. The invention is a stand-by engineering measure aiming at the problems that the design of the built ship lock has no anti-cavitation measure or has unsuitable anti-cavitation measure, the section of the ship lock valve has obvious cavitation, and the cavitation can cause adverse effect to operational equipment of the ship lock. The door head body has simple construction, low working load and convenient maintenance, and can well solve the cavitation problem of the built ship lock valve.