The invention discloses a sealed type controllable ball valve comprising a valve body, a valve rod and a handle. A ball body is arranged in the valve body, the handle is fixed to the top of the valverod through a bolt, and the bottom end of the valve rod extends into the valve body and is fixedly connected with the top face of the ball body. The valve body comprises a left half valve body and a right half valve body which are fixedly connected through a screw. A valve cavity with the open left side is arranged in the right half valve body, the inner side of a valve cavity of the right half valve body are provided with a step clamping part and a sealing ring clamp groove, and a step abutting part and an annular boss are fixed to the right side face of the left half valve body. A metal winding gasket is fixed between the abutting-pressing faces of the step clamping part and the step abutting part, an O-shaped sealing ring is fixed in the sealing ring clamp groove, and a fan-shaped flowpass is arranged in the center of the ball body. According to the sealed type controllable ball valve, structural arrangement is reasonable, assembling is facilitated, the assembling efficiency is improved, the stable using reliability of the ball valve can also be ensured, the accuracy of flow control is improved, a flow system is accurately controlled, the using stability is good, the adaptability is high, and the practicability is good.