The invention relates to a ball valve with a scour-prevention valve base. The ball valve is characterized in that a positioning groove and a straight groove are formed in the bottom face of a runner,the positioning groove is of a fan arc structure with the vertical axis of the ball valve as the center line, the straight groove is formed under the horizontal axis of the ball valve, one end of thestraight groove communicates with one end of the positioning groove, the other end of the straight groove extends to a near runner opening, an adjusting device is arranged in the runner, the adjustingdevice comprises a ball clack, a compression spring, a telescopic rod, a positioning rod and an adjusting sleeve, a lower outer rod and a lower inner rod with the axes consistent with the axis of theadjusting sleeve are arranged on the lower middle portion of a valve body, the upper end of the lower outer rod is fixedly connected with the adjusting sleeve, the lower end of the lower outer rod extends out of the lower end of the valve body, the lower inner rod is arranged in the lower outer rod, the upper end of the lower inner rod is provided with a pull rod with the vertical section in an inverted right trapezoid, the pull rod extends to the upper portion of an inner cavity of the adjusting sleeve through an adjusting clamping groove, and the lower end of the lower inner rod extends outof the lower end face of the lower outer rod. The beneficial effects that the valve base is good in scour prevention, the service life is long, and safety is high are achieved.