A double-ball combined valve comprises a long-barrel-shaped valve body, two ball valve mechanisms, a needle type valve mechanism and a screw plug, wherein a main medium flow channel is formed in the center of the valve body, the valve seats and the valve balls of the two ball valve mechanisms are arranged in the main medium flow channel, the side face of the valve body is provided with a screw plug installation hole and a needle type valve mechanism assembly hole, the valve body is provided with a first sub-flow channel extending from a segment of main medium flow channel between the two ball valve mechanisms to the needle type valve mechanism assembly hole, the valve body is provided with a second sub-flow channel through which the needle type valve mechanism assembly hole and the screw plug installing hole can be communicated, a double-screw bolt of the screw plug is connected to the screw plug installation hole in a threaded mode, the needle type valve mechanism assembly hole is provided with the needle type valve mechanism, and a conical valve clack of the needle type valve mechanism is arranged in an outlet, in the needle type valve mechanism assembly hole, of the first sub-flow channel. The two independent ball valve mechanisms, the needle type valve mechanism and the screw plug are connected to the same valve body, and the double-ball combined valve is reasonable and compact in structure, multifunctional, good in rigidity, small in number of hidden danger leakage points, high in reliability and long in service life.