This paper discloses a bleed valve in pit, and including urceolus and lower clutch, the top of urceolus is equipped with suppresses the hole, still includes the piston cylinder and locates the piston assembly in the piston cylinder, the piston cylinder includes first barrel and the second barrel that is connected, and first barrel setting is in the inboard of urceolus, and the lower extreme of second barrel extends the outside of urceolus, the bottom of urceolus is passed through the second barrel and is connected with the lower clutch, and the lower extreme of second barrel is provided with the exhaust hole, and piston assembly's bottom shutoff is in the through -hole department of lower clutch, piston assembly's the outside is equipped with first step, constitutes annular driven cavity body between first step and the second barrel, driven cavity body with suppress the hole intercommunication for transmit hydraulic pressure to driven cavity body from suppressing the hole, and the action of drive RAM subassembly. The utility model relates to a marine producing well upper portion well completion instrument field, this application discloses a bleed valve in pit, and unstable pressure's state in the time of can avoiding appearing opening and closing reaches accurate control and steady exhaust.