The invention discloses a flexible self-adaption petroleum pipeline ball valve. The flexible self-adaption petroleum pipeline ball valve structurally comprises a valve body, a flexible ball, a seal ring, a shaft, a driver, a self-adjusting mechanism and a hand wheel. The flexible ball is arranged in the valve body. The seal ring is arranged between the flexible ball and the valve body. The top ofthe flexible ball is connected with the driver through the shaft. The side face of the driver is connected with the hand wheel. The self-adjusting mechanism is arranged above the driver and connectedwith the shaft. The flexible ball is composed of a ball shell, an elastic sheet, a connecting column, an ejection mechanism and a runner. The ball shell is arranged in the valve body and provided withthe penetrating runner, the connecting column is connected between the runner and the ball shell, the runner is provided with the elastic sheet, the part between the elastic sheet and the ball shellis a cavity, and the ejection mechanism is arranged in the cavity and fixedly connected with the ball shell. The flexible self-adaption petroleum pipeline ball valve has the beneficial effects that when petroleum is heated and expanded, the volume is enlarged for reducing extrusion damage to the ball, static electricity increasing under the heating situation is avoided, and safety is improved.